* Added recalculation

MealPlan.Api/Controllers/RecipeManagementController.cs

@@ -13,13 +13,16 @@ public class RecipeManagementController : ControllerBase
 {
     private readonly IRecipeManagementService _managementService;
     private readonly IRecipeExcelService _excelService;
+    private readonly IRecipeCalorieRecalculationService _calorieRecalculation;
 
     public RecipeManagementController(
         IRecipeManagementService managementService,
-        IRecipeExcelService excelService)
+        IRecipeExcelService excelService,
+        IRecipeCalorieRecalculationService calorieRecalculation)
     {
         _managementService = managementService;
         _excelService = excelService;
+        _calorieRecalculation = calorieRecalculation;
     }
 
     /// <summary>Creates a new recipe with ingredients and steps.</summary>
@@ -90,4 +93,26 @@ public class RecipeManagementController : ControllerBase
         var result = await _managementService.RecalculateAllMacrosFromCatalogAsync(ct);
         return Ok(result);
     }
+
+    /// <summary>Scales or AI-adjusts ingredient amounts to match a calorie target.</summary>
+    [HttpPost("{id:int}/recalculate-calories")]
+    [ProducesResponseType(typeof(RecalculateRecipeCaloriesResultDto), StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    public async Task<IActionResult> RecalculateCalories(
+        int id,
+        [FromBody] RecalculateRecipeCaloriesRequestDto request,
+        CancellationToken ct)
+    {
+        try
+        {
+            var result = await _calorieRecalculation.RecalculateAsync(id, request, ct);
+            return result is null
+                ? NotFound(new { error = $"Recipe {id} was not found." })
+                : Ok(result);
+        }
+        catch (InvalidOperationException ex)
+        {
+            return BadRequest(new { error = ex.Message });
+        }
+    }
 }

MealPlan.Api/Program.cs

@@ -69,6 +69,7 @@ builder.Services.AddScoped<ITokenService, TokenService>();
 builder.Services.AddScoped<IAuthService, AuthService>();
 builder.Services.AddScoped<IRecipeService, RecipeService>();
 builder.Services.AddScoped<IRecipeManagementService, RecipeManagementService>();
+builder.Services.AddScoped<IRecipeCalorieRecalculationService, RecipeCalorieRecalculationService>();
 builder.Services.AddScoped<IRecipeExcelService, RecipeExcelService>();
 builder.Services.AddScoped<IDietTrackingService, DietTrackingService>();
 builder.Services.AddScoped<IIngredientCatalogService, IngredientCatalogService>();

meal-plan-frontend-angular/public/i18n/en.json

@@ -160,7 +160,16 @@
     "noIngredients": "No ingredients listed.",
     "noSteps": "No steps listed.",
     "kcal": "{{count}} kcal",
-    "minutes": "{{count}} min"
+    "minutes": "{{count}} min",
+    "recalculateCaloriesTitle": "Adjust calories",
+    "recalculateCaloriesHint": "Enter a target kcal — ingredient amounts will be scaled (catalog + AI).",
+    "targetCalories": "Target kcal",
+    "recalculate": "Recalculate",
+    "applyRecalculation": "Save changes",
+    "recalculatePreview": "Preview: {{previous}} → {{next}} kcal (target: {{target}})",
+    "recalculateUnlinkedHint": "{{count}} ingredient(s) not linked to the catalog — values may be less accurate.",
+    "recalculateCaloriesInvalid": "Enter calories between 50 and 10000 kcal.",
+    "recalculateCaloriesFailed": "Could not recalculate the recipe."
   },
   "manage": {
     "title": "Manage Meals",

meal-plan-frontend-angular/public/i18n/pl.json

@@ -164,7 +164,16 @@
     "noIngredients": "Brak składników.",
     "noSteps": "Brak kroków.",
     "kcal": "{{count}} kcal",
-    "minutes": "{{count}} min"
+    "minutes": "{{count}} min",
+    "recalculateCaloriesTitle": "Dopasuj kaloryczność",
+    "recalculateCaloriesHint": "Podaj docelową liczbę kcal — przeliczymy gramaturę składników (katalog + AI).",
+    "targetCalories": "Docelowe kcal",
+    "recalculate": "Przelicz",
+    "applyRecalculation": "Zapisz zmiany",
+    "recalculatePreview": "Podgląd: {{previous}} → {{next}} kcal (cel: {{target}})",
+    "recalculateUnlinkedHint": "{{count}} składnik(ów) bez powiązania z katalogiem — wartości mogą być mniej dokładne.",
+    "recalculateCaloriesInvalid": "Podaj kaloryczność między 50 a 10000 kcal.",
+    "recalculateCaloriesFailed": "Nie udało się przeliczyć przepisu."
   },
   "manage": {
     "title": "Zarządzaj posiłkami",

meal-plan-frontend-angular/src/app/core/models/recipe.models.ts

@@ -98,3 +98,18 @@ export interface RecipeMacroRecalcResult {
   recipesUpdated: number;
   unlinkedIngredientRows: number;
 }
+
+export interface RecalculateRecipeCaloriesResult {
+  recipeId: number;
+  previousCalories?: number | null;
+  targetCalories: number;
+  newCalories?: number | null;
+  newProtein?: number | null;
+  newFat?: number | null;
+  newCarbs?: number | null;
+  applied: boolean;
+  method: string;
+  unlinkedIngredientCount: number;
+  ingredients: Ingredient[];
+  recipe?: RecipeDetail | null;
+}

meal-plan-frontend-angular/src/app/core/services/recipe-management.service.ts

@@ -6,6 +6,7 @@ import {
   RecipeDetail,
   RecipeImportResult,
   RecipeMacroRecalcResult,
+  RecalculateRecipeCaloriesResult,
 } from '../models/recipe.models';
 
 @Injectable({ providedIn: 'root' })
@@ -34,6 +35,17 @@ export class RecipeManagementService {
     return this.http.post<RecipeMacroRecalcResult>('/api/recipes/recalculate-macros', {});
   }
 
+  recalculateRecipeCalories(
+    recipeId: number,
+    targetCalories: number,
+    apply = false,
+  ): Observable<RecalculateRecipeCaloriesResult> {
+    return this.http.post<RecalculateRecipeCaloriesResult>(
+      `/api/recipes/${recipeId}/recalculate-calories`,
+      { targetCalories, apply },
+    );
+  }
+
   private toPayload(input: CreateRecipeInput) {
     return {
       name: input.name,

meal-plan-frontend-angular/src/app/features/recipe-detail/recipe-detail-page.component.ts

@@ -37,7 +37,7 @@ import { extractApiError } from '../../core/utils/api-error.util';
       }
 
       @if (!loading() && !error() && recipe()) {
-        <app-recipe-detail-view [recipe]="recipe()!" />
+        <app-recipe-detail-view [recipe]="recipe()!" (recipeUpdated)="recipe.set($event)" />
       }
     </div>
   `,

meal-plan-frontend-angular/src/app/features/recipes/recipe-detail-view.component.ts

@@ -1,7 +1,11 @@
-import { Component, Input, computed, signal } from '@angular/core';
+import { Component, EventEmitter, Input, OnChanges, Output, computed, inject, signal } from '@angular/core';
-import { TranslatePipe } from '@ngx-translate/core';
+import { NgClass } from '@angular/common';
-import { RecipeDetail } from '../../core/models/recipe.models';
+import { FormsModule } from '@angular/forms';
+import { TranslatePipe, TranslateService } from '@ngx-translate/core';
+import { RecipeManagementService } from '../../core/services/recipe-management.service';
+import { RecipeDetail, RecalculateRecipeCaloriesResult } from '../../core/models/recipe.models';
 import { CategoryBadgeComponent } from '../../shared/components/category-badge.component';
+import { extractApiError } from '../../core/utils/api-error.util';
 import { nextSort, sortBy, sortIndicator, type SortDirection } from '../../core/utils/sort.util';
 
 type IngredientSortColumn = 'name' | 'amount';
@@ -9,71 +13,84 @@ type IngredientSortColumn = 'name' | 'amount';
 @Component({
   selector: 'app-recipe-detail-view',
   standalone: true,
-  imports: [TranslatePipe, CategoryBadgeComponent],
+  imports: [NgClass, FormsModule, TranslatePipe, CategoryBadgeComponent],
   template: `
     <article class="space-y-8">
       <header class="space-y-3">
-        <app-category-badge [category]="recipe.mealCategory" />
+        <app-category-badge [category]="displayRecipe().mealCategory" />
-        <h1 class="text-3xl font-extrabold tracking-tight">{{ recipe.name }}</h1>
+        <h1 class="text-3xl font-extrabold tracking-tight">{{ displayRecipe().name }}</h1>
-        @if (recipe.prepTimeMinutes != null) {
+        @if (displayRecipe().prepTimeMinutes != null) {
           <p class="inline-flex items-center gap-1.5 text-sm text-slate-500 dark:text-slate-400">
             <span aria-hidden="true">⏱</span>
-            {{ 'recipes.prepTime' | translate: { count: recipe.prepTimeMinutes } }}
+            {{ 'recipes.prepTime' | translate: { count: displayRecipe().prepTimeMinutes } }}
           </p>
         }
       </header>
 
       <section class="grid grid-cols-2 gap-3 sm:grid-cols-4">
-        <div class="rounded-2xl border border-slate-200 bg-white px-4 py-3 text-center dark:border-slate-800 dark:bg-slate-900">
+        @for (macro of macroCards(); track macro.label) {
-          <p class="text-2xl font-extrabold text-orange-500">
+          <div
-            {{ recipe.calories ?? '—' }}
+            class="rounded-2xl border px-4 py-3 text-center"
-            @if (recipe.calories != null) {
+            [ngClass]="
-              <span class="text-sm font-semibold"> kcal</span>
+              macro.highlight
+                ? 'border-brand-300 bg-brand-50 dark:border-brand-700 dark:bg-brand-950/30'
+                : 'border-slate-200 bg-white dark:border-slate-800 dark:bg-slate-900'
+            "
+          >
+            <p class="text-2xl font-extrabold" [class]="macro.accent">
+              {{ macro.value ?? '—' }}
+              @if (macro.value != null) {
+                <span class="text-sm font-semibold"> {{ macro.suffix }}</span>
+              }
+            </p>
+            <p class="mt-0.5 text-xs font-medium uppercase tracking-wide text-slate-500 dark:text-slate-400">
+              {{ macro.label | translate }}
+            </p>
+          </div>
+        }
+      </section>
+
+      <section class="card space-y-3 p-4">
+        <h2 class="text-sm font-bold">{{ 'recipes.recalculateCaloriesTitle' | translate }}</h2>
+        <p class="text-sm text-slate-500 dark:text-slate-400">{{ 'recipes.recalculateCaloriesHint' | translate }}</p>
+        <div class="flex flex-wrap items-end gap-3">
+          <label class="block text-sm">
+            {{ 'recipes.targetCalories' | translate }}
+            <input type="number" min="50" max="10000" class="input mt-1 w-36" [(ngModel)]="targetCalories" (ngModelChange)="preview.set(null)" />
+          </label>
+          <button type="button" class="btn-secondary" [disabled]="pending() || applyPending()" (click)="runRecalculate(false)">
+            ↻ {{ 'recipes.recalculate' | translate }}
+          </button>
+          @if (showingPreview()) {
+            <button type="button" class="btn-primary" [disabled]="pending() || applyPending()" (click)="runRecalculate(true)">
+              {{ 'recipes.applyRecalculation' | translate }}
+            </button>
+          }
+        </div>
+        @if (showingPreview() && preview()) {
+          <p class="text-sm text-brand-700 dark:text-brand-300">
+            {{
+              'recipes.recalculatePreview'
+                | translate: {
+                    previous: preview()!.previousCalories ?? '—',
+                    next: preview()!.newCalories ?? '—',
+                    target: preview()!.targetCalories,
+                  }
+            }}
+            @if (preview()!.unlinkedIngredientCount > 0) {
+              {{ 'recipes.recalculateUnlinkedHint' | translate: { count: preview()!.unlinkedIngredientCount } }}
             }
           </p>
-          <p class="mt-0.5 text-xs font-medium uppercase tracking-wide text-slate-500 dark:text-slate-400">
+        }
-            {{ 'recipes.calories' | translate }}
+        @if (error()) {
-          </p>
+          <p role="alert" class="text-sm text-red-600 dark:text-red-400">{{ error() }}</p>
-        </div>
+        }
-        <div class="rounded-2xl border border-slate-200 bg-white px-4 py-3 text-center dark:border-slate-800 dark:bg-slate-900">
-          <p class="text-2xl font-extrabold text-brand-600">
-            {{ recipe.protein ?? '—' }}
-            @if (recipe.protein != null) {
-              <span class="text-sm font-semibold"> g</span>
-            }
-          </p>
-          <p class="mt-0.5 text-xs font-medium uppercase tracking-wide text-slate-500 dark:text-slate-400">
-            {{ 'recipes.protein' | translate }}
-          </p>
-        </div>
-        <div class="rounded-2xl border border-slate-200 bg-white px-4 py-3 text-center dark:border-slate-800 dark:bg-slate-900">
-          <p class="text-2xl font-extrabold text-amber-500">
-            {{ recipe.fat ?? '—' }}
-            @if (recipe.fat != null) {
-              <span class="text-sm font-semibold"> g</span>
-            }
-          </p>
-          <p class="mt-0.5 text-xs font-medium uppercase tracking-wide text-slate-500 dark:text-slate-400">
-            {{ 'recipes.fat' | translate }}
-          </p>
-        </div>
-        <div class="rounded-2xl border border-slate-200 bg-white px-4 py-3 text-center dark:border-slate-800 dark:bg-slate-900">
-          <p class="text-2xl font-extrabold text-sky-500">
-            {{ recipe.carbs ?? '—' }}
-            @if (recipe.carbs != null) {
-              <span class="text-sm font-semibold"> g</span>
-            }
-          </p>
-          <p class="mt-0.5 text-xs font-medium uppercase tracking-wide text-slate-500 dark:text-slate-400">
-            {{ 'recipes.carbs' | translate }}
-          </p>
-        </div>
       </section>
 
       <div class="grid gap-8 lg:grid-cols-[1fr_1.4fr]">
         <section>
           <h2 class="text-lg font-bold">{{ 'recipes.ingredients' | translate }}</h2>
-          @if (recipe.ingredients.length === 0) {
+          @if (displayRecipe().ingredients.length === 0) {
             <p class="mt-3 text-sm text-slate-500">{{ 'recipes.noIngredients' | translate }}</p>
           } @else {
             <div class="mt-4 overflow-hidden rounded-2xl border border-slate-200 dark:border-slate-800">
@@ -89,8 +106,20 @@ type IngredientSortColumn = 'name' | 'amount';
                 @for (ing of sortedIngredients(); track ing.id) {
                   <li class="grid grid-cols-[1fr_auto] items-center px-4 py-3 text-sm">
                     <span>{{ ing.name }}</span>
-                    <span class="font-medium text-slate-500 dark:text-slate-400">
+                    <span
+                      class="font-medium"
+                      [ngClass]="
+                        amountChanged(ing.id, ing.amountGrams)
+                          ? 'text-brand-700 dark:text-brand-300'
+                          : 'text-slate-500 dark:text-slate-400'
+                      "
+                    >
                       {{ formatAmount(ing.amountGrams, ing.unit) }}
+                      @if (amountChanged(ing.id, ing.amountGrams)) {
+                        <span class="ml-2 text-xs text-slate-400 line-through">
+                          {{ formatAmount(originalAmounts().get(ing.id) ?? null, ing.unit) }}
+                        </span>
+                      }
                     </span>
                   </li>
                 }
@@ -101,11 +130,11 @@ type IngredientSortColumn = 'name' | 'amount';
 
         <section>
           <h2 class="text-lg font-bold">{{ 'recipes.preparation' | translate }}</h2>
-          @if (recipe.steps.length === 0) {
+          @if (displayRecipe().steps.length === 0) {
             <p class="mt-3 text-sm text-slate-500">{{ 'recipes.noSteps' | translate }}</p>
           } @else {
             <ol class="mt-4 space-y-4">
-              @for (step of recipe.steps; track step.id) {
+              @for (step of displayRecipe().steps; track step.id) {
                 <li class="flex gap-4">
                   <span class="grid h-8 w-8 shrink-0 place-items-center rounded-full bg-brand-600 text-sm font-bold text-white">
                     {{ step.stepNumber }}
@@ -122,21 +151,73 @@ type IngredientSortColumn = 'name' | 'amount';
     </article>
   `,
 })
-export class RecipeDetailViewComponent {
+export class RecipeDetailViewComponent implements OnChanges {
+  private readonly management = inject(RecipeManagementService);
+  private readonly translate = inject(TranslateService);
+
   @Input({ required: true }) recipe!: RecipeDetail;
+  @Output() recipeUpdated = new EventEmitter<RecipeDetail>();
+
+  readonly preview = signal<RecalculateRecipeCaloriesResult | null>(null);
+  readonly pending = signal(false);
+  readonly applyPending = signal(false);
+  readonly error = signal<string | null>(null);
+  targetCalories = '';
 
   readonly ingredientSort = signal<{ column: IngredientSortColumn; direction: SortDirection }>({
     column: 'name',
     direction: 'asc',
   });
 
+  readonly originalAmounts = computed(
+    () => new Map(this.recipe.ingredients.map((ing) => [ing.id, ing.amountGrams])),
+  );
+
+  readonly displayRecipe = computed(() => {
+    const preview = this.preview();
+    if (preview?.applied && preview.recipe) return preview.recipe;
+    if (preview) {
+      return {
+        ...this.recipe,
+        calories: preview.newCalories ?? this.recipe.calories,
+        protein: preview.newProtein ?? this.recipe.protein,
+        fat: preview.newFat ?? this.recipe.fat,
+        carbs: preview.newCarbs ?? this.recipe.carbs,
+        ingredients: preview.ingredients,
+      };
+    }
+    return this.recipe;
+  });
+
+  readonly showingPreview = computed(() => {
+    const preview = this.preview();
+    return preview != null && !preview.applied;
+  });
+
+  readonly macroCards = computed(() => {
+    const recipe = this.displayRecipe();
+    const highlight = this.showingPreview();
+    return [
+      { label: 'recipes.calories', value: recipe.calories, suffix: 'kcal', accent: 'text-orange-500', highlight },
+      { label: 'recipes.protein', value: recipe.protein, suffix: 'g', accent: 'text-brand-600', highlight },
+      { label: 'recipes.fat', value: recipe.fat, suffix: 'g', accent: 'text-amber-500', highlight },
+      { label: 'recipes.carbs', value: recipe.carbs, suffix: 'g', accent: 'text-sky-500', highlight },
+    ];
+  });
+
   readonly sortedIngredients = computed(() => {
     const { column, direction } = this.ingredientSort();
-    return sortBy(this.recipe.ingredients, direction, (ing) =>
+    return sortBy(this.displayRecipe().ingredients, direction, (ing) =>
       column === 'name' ? ing.name : ing.amountGrams,
     );
   });
 
+  ngOnChanges(): void {
+    if (this.recipe && !this.targetCalories) {
+      this.targetCalories = this.recipe.calories != null ? String(this.recipe.calories) : '';
+    }
+  }
+
   formatAmount(amount: number | null, unit: string | null): string {
     if (amount == null && !unit) return '';
     if (amount == null) return unit ?? '';
@@ -144,6 +225,12 @@ export class RecipeDetailViewComponent {
     return unit ? `${display} ${unit}` : `${display} g`;
   }
 
+  amountChanged(id: number, amount: number | null): boolean {
+    if (!this.showingPreview()) return false;
+    const previous = this.originalAmounts().get(id);
+    return previous != null && amount != null && previous !== amount;
+  }
+
   toggleIngredientSort(column: IngredientSortColumn): void {
     this.ingredientSort.update((current) => nextSort(current, column));
   }
@@ -151,4 +238,34 @@ export class RecipeDetailViewComponent {
   ingredientIndicator(column: IngredientSortColumn): string {
     return sortIndicator(this.ingredientSort(), column);
   }
+
+  runRecalculate(apply: boolean): void {
+    const target = Number(this.targetCalories);
+    if (!Number.isFinite(target) || target < 50) {
+      this.error.set(this.translate.instant('recipes.recalculateCaloriesInvalid'));
+      return;
+    }
+
+    this.error.set(null);
+    if (apply) this.applyPending.set(true);
+    else this.pending.set(true);
+
+    this.management.recalculateRecipeCalories(this.recipe.id, target, apply).subscribe({
+      next: (result) => {
+        this.preview.set(result);
+        if (result.applied && result.recipe) {
+          this.recipe = result.recipe;
+          this.recipeUpdated.emit(result.recipe);
+          this.preview.set(null);
+        }
+        this.pending.set(false);
+        this.applyPending.set(false);
+      },
+      error: (err) => {
+        this.error.set(extractApiError(err, this.translate.instant('recipes.recalculateCaloriesFailed')));
+        this.pending.set(false);
+        this.applyPending.set(false);
+      },
+    });
+  }
 }

meal-plan-frontend/src/api/recipe-management.api.ts

@@ -1,6 +1,6 @@
 import { api } from "./axiosInstance";
 import type { RecipeDetail } from "@/types/recipe.types";
-import type { CreateRecipeInput, RecipeImportResult, RecipeMacroRecalcResult } from "@/types/recipe-management.types";
+import type { CreateRecipeInput, RecipeImportResult, RecipeMacroRecalcResult, RecalculateRecipeCaloriesResult } from "@/types/recipe-management.types";
 
 function toPayload(input: CreateRecipeInput) {
   return {
@@ -55,3 +55,15 @@ export async function recalculateAllRecipeMacros(): Promise<RecipeMacroRecalcRes
   const { data } = await api.post<RecipeMacroRecalcResult>("/recipes/recalculate-macros");
   return data;
 }
+
+export async function recalculateRecipeCalories(
+  recipeId: number,
+  targetCalories: number,
+  apply = false,
+): Promise<RecalculateRecipeCaloriesResult> {
+  const { data } = await api.post<RecalculateRecipeCaloriesResult>(
+    `/recipes/${recipeId}/recalculate-calories`,
+    { targetCalories, apply },
+  );
+  return data;
+}

meal-plan-frontend/src/components/recipes/RecipeDetail.tsx

@@ -1,8 +1,11 @@
 import { useMemo, useState } from "react";
-import { Clock } from "lucide-react";
+import { Clock, Loader2, RefreshCw, Save } from "lucide-react";
 import { useTranslation } from "react-i18next";
+import { recalculateRecipeCalories } from "@/api/recipe-management.api";
+import { extractApiError } from "@/api/axiosInstance";
 import { CategoryBadge } from "@/components/ui/CategoryBadge";
 import type { RecipeDetail as RecipeDetailModel } from "@/types/recipe.types";
+import type { RecalculateRecipeCaloriesResult } from "@/types/recipe-management.types";
 import { nextSort, sortBy, sortIndicator, type SortDirection } from "@/utils/sort.util";
 
 type IngredientSortColumn = "name" | "amount";
@@ -12,11 +15,18 @@ interface MacroProps {
   value: number | null;
   suffix: string;
   accent: string;
+  highlight?: boolean;
 }
 
-function Macro({ label, value, suffix, accent }: MacroProps) {
+function Macro({ label, value, suffix, accent, highlight }: MacroProps) {
   return (
-    <div className="rounded-2xl border border-slate-200 bg-white px-4 py-3 text-center dark:border-slate-800 dark:bg-slate-900">
+    <div
+      className={`rounded-2xl border px-4 py-3 text-center ${
+        highlight
+          ? "border-brand-300 bg-brand-50 dark:border-brand-700 dark:bg-brand-950/30"
+          : "border-slate-200 bg-white dark:border-slate-800 dark:bg-slate-900"
+      }`}
+    >
       <p className={`text-2xl font-extrabold ${accent}`}>
         {value != null ? value : "—"}
         {value != null && <span className="text-sm font-semibold"> {suffix}</span>}
@@ -37,51 +47,198 @@ function formatAmount(amount: number | null, unit: string | null): string {
 
 interface RecipeDetailProps {
   recipe: RecipeDetailModel;
+  onRecipeUpdated?: (recipe: RecipeDetailModel) => void;
 }
 
-export function RecipeDetail({ recipe }: RecipeDetailProps) {
+function mergePreview(recipe: RecipeDetailModel, preview: RecalculateRecipeCaloriesResult): RecipeDetailModel {
+  return {
+    ...recipe,
+    calories: preview.newCalories ?? recipe.calories,
+    protein: preview.newProtein ?? recipe.protein,
+    fat: preview.newFat ?? recipe.fat,
+    carbs: preview.newCarbs ?? recipe.carbs,
+    ingredients: preview.ingredients.map((ing) => ({
+      id: ing.id,
+      name: ing.name,
+      amountGrams: ing.amountGrams,
+      unit: ing.unit,
+      sortOrder: ing.sortOrder,
+      catalogItemId: ing.catalogItemId,
+    })),
+  };
+}
+
+export function RecipeDetail({ recipe, onRecipeUpdated }: RecipeDetailProps) {
   const { t } = useTranslation();
   const [ingredientSort, setIngredientSort] = useState<{
     column: IngredientSortColumn;
     direction: SortDirection;
   }>({ column: "name", direction: "asc" });
+  const [targetCalories, setTargetCalories] = useState(
+    recipe.calories != null ? String(recipe.calories) : "",
+  );
+  const [preview, setPreview] = useState<RecalculateRecipeCaloriesResult | null>(null);
+  const [pending, setPending] = useState(false);
+  const [applyPending, setApplyPending] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const displayRecipe = useMemo(() => {
+    if (preview?.applied && preview.recipe) return preview.recipe;
+    if (preview) return mergePreview(recipe, preview);
+    return recipe;
+  }, [preview, recipe]);
+
+  const originalAmounts = useMemo(
+    () => new Map(recipe.ingredients.map((ing) => [ing.id, ing.amountGrams])),
+    [recipe.ingredients],
+  );
 
   const sortedIngredients = useMemo(
     () =>
-      sortBy(recipe.ingredients, ingredientSort.direction, (ing) =>
+      sortBy(displayRecipe.ingredients, ingredientSort.direction, (ing) =>
         ingredientSort.column === "name" ? ing.name : ing.amountGrams,
       ),
-    [recipe.ingredients, ingredientSort],
+    [displayRecipe.ingredients, ingredientSort],
   );
 
   const toggleIngredientSort = (column: IngredientSortColumn) => {
     setIngredientSort((current) => nextSort(current, column));
   };
 
+  const runRecalculate = async (apply: boolean) => {
+    const target = Number(targetCalories);
+    if (!Number.isFinite(target) || target < 50) {
+      setError(t("recipes.recalculateCaloriesInvalid"));
+      return;
+    }
+
+    setError(null);
+    if (apply) setApplyPending(true);
+    else setPending(true);
+
+    try {
+      const result = await recalculateRecipeCalories(recipe.id, target, apply);
+      setPreview(result);
+      if (result.applied && result.recipe) {
+        onRecipeUpdated?.(result.recipe);
+        setPreview(null);
+      }
+    } catch (e) {
+      setError(extractApiError(e, t("recipes.recalculateCaloriesFailed")));
+    } finally {
+      setPending(false);
+      setApplyPending(false);
+    }
+  };
+
+  const showingPreview = preview != null && !preview.applied;
+
   return (
     <article className="space-y-8">
       <header className="space-y-3">
-        <CategoryBadge category={recipe.mealCategory} />
+        <CategoryBadge category={displayRecipe.mealCategory} />
-        <h1 className="text-3xl font-extrabold tracking-tight">{recipe.name}</h1>
+        <h1 className="text-3xl font-extrabold tracking-tight">{displayRecipe.name}</h1>
-        {recipe.prepTimeMinutes != null && (
+        {displayRecipe.prepTimeMinutes != null && (
           <p className="inline-flex items-center gap-1.5 text-sm text-slate-500 dark:text-slate-400">
             <Clock className="h-4 w-4" />
-            {t("recipes.prepTime", { count: recipe.prepTimeMinutes })}
+            {t("recipes.prepTime", { count: displayRecipe.prepTimeMinutes })}
           </p>
         )}
       </header>
 
       <section className="grid grid-cols-2 gap-3 sm:grid-cols-4">
-        <Macro label={t("recipes.calories")} value={recipe.calories} suffix="kcal" accent="text-orange-500" />
+        <Macro
-        <Macro label={t("recipes.protein")} value={recipe.protein} suffix="g" accent="text-brand-600" />
+          label={t("recipes.calories")}
-        <Macro label={t("recipes.fat")} value={recipe.fat} suffix="g" accent="text-amber-500" />
+          value={displayRecipe.calories}
-        <Macro label={t("recipes.carbs")} value={recipe.carbs} suffix="g" accent="text-sky-500" />
+          suffix="kcal"
+          accent="text-orange-500"
+          highlight={showingPreview}
+        />
+        <Macro
+          label={t("recipes.protein")}
+          value={displayRecipe.protein}
+          suffix="g"
+          accent="text-brand-600"
+          highlight={showingPreview}
+        />
+        <Macro
+          label={t("recipes.fat")}
+          value={displayRecipe.fat}
+          suffix="g"
+          accent="text-amber-500"
+          highlight={showingPreview}
+        />
+        <Macro
+          label={t("recipes.carbs")}
+          value={displayRecipe.carbs}
+          suffix="g"
+          accent="text-sky-500"
+          highlight={showingPreview}
+        />
+      </section>
+
+      <section className="card space-y-3 p-4">
+        <h2 className="text-sm font-bold">{t("recipes.recalculateCaloriesTitle")}</h2>
+        <p className="text-sm text-slate-500">{t("recipes.recalculateCaloriesHint")}</p>
+        <div className="flex flex-wrap items-end gap-3">
+          <label className="block text-sm">
+            {t("recipes.targetCalories")}
+            <input
+              type="number"
+              min={50}
+              max={10000}
+              className="input mt-1 w-36"
+              value={targetCalories}
+              onChange={(e) => {
+                setTargetCalories(e.target.value);
+                setPreview(null);
+              }}
+            />
+          </label>
+          <button
+            type="button"
+            className="btn-secondary"
+            disabled={pending || applyPending}
+            onClick={() => void runRecalculate(false)}
+          >
+            {pending ? <Loader2 className="h-4 w-4 animate-spin" /> : <RefreshCw className="h-4 w-4" />}
+            {t("recipes.recalculate")}
+          </button>
+          {showingPreview ? (
+            <button
+              type="button"
+              className="btn-primary"
+              disabled={pending || applyPending}
+              onClick={() => void runRecalculate(true)}
+            >
+              {applyPending ? <Loader2 className="h-4 w-4 animate-spin" /> : <Save className="h-4 w-4" />}
+              {t("recipes.applyRecalculation")}
+            </button>
+          ) : null}
+        </div>
+        {showingPreview ? (
+          <p className="text-sm text-brand-700 dark:text-brand-300">
+            {t("recipes.recalculatePreview", {
+              previous: preview.previousCalories ?? "—",
+              next: preview.newCalories ?? "—",
+              target: preview.targetCalories,
+            })}
+            {preview.unlinkedIngredientCount > 0
+              ? ` ${t("recipes.recalculateUnlinkedHint", { count: preview.unlinkedIngredientCount })}`
+              : ""}
+          </p>
+        ) : null}
+        {error ? (
+          <p role="alert" className="text-sm text-red-600 dark:text-red-400">
+            {error}
+          </p>
+        ) : null}
       </section>
 
       <div className="grid gap-8 lg:grid-cols-[1fr_1.4fr]">
         <section>
           <h2 className="text-lg font-bold">{t("recipes.ingredients")}</h2>
-          {recipe.ingredients.length === 0 ? (
+          {displayRecipe.ingredients.length === 0 ? (
             <p className="mt-3 text-sm text-slate-500">{t("recipes.noIngredients")}</p>
           ) : (
             <div className="mt-4 overflow-hidden rounded-2xl border border-slate-200 dark:border-slate-800">
@@ -104,14 +261,31 @@ export function RecipeDetail({ recipe }: RecipeDetailProps) {
                 </button>
               </div>
               <ul className="divide-y divide-slate-200 dark:divide-slate-800">
-                {sortedIngredients.map((ing) => (
+                {sortedIngredients.map((ing) => {
-                  <li key={ing.id} className="grid grid-cols-[1fr_auto] items-center px-4 py-3 text-sm">
+                  const previous = originalAmounts.get(ing.id);
-                    <span>{ing.name}</span>
+                  const changed =
-                    <span className="font-medium text-slate-500 dark:text-slate-400">
+                    showingPreview &&
-                      {formatAmount(ing.amountGrams, ing.unit)}
+                    previous != null &&
-                    </span>
+                    ing.amountGrams != null &&
-                  </li>
+                    previous !== ing.amountGrams;
-                ))}
+                  return (
+                    <li key={ing.id} className="grid grid-cols-[1fr_auto] items-center px-4 py-3 text-sm">
+                      <span>{ing.name}</span>
+                      <span
+                        className={`font-medium ${
+                          changed ? "text-brand-700 dark:text-brand-300" : "text-slate-500 dark:text-slate-400"
+                        }`}
+                      >
+                        {formatAmount(ing.amountGrams, ing.unit)}
+                        {changed ? (
+                          <span className="ml-2 text-xs text-slate-400 line-through">
+                            {formatAmount(previous, ing.unit)}
+                          </span>
+                        ) : null}
+                      </span>
+                    </li>
+                  );
+                })}
               </ul>
             </div>
           )}
@@ -119,11 +293,11 @@ export function RecipeDetail({ recipe }: RecipeDetailProps) {
 
         <section>
           <h2 className="text-lg font-bold">{t("recipes.preparation")}</h2>
-          {recipe.steps.length === 0 ? (
+          {displayRecipe.steps.length === 0 ? (
             <p className="mt-3 text-sm text-slate-500">{t("recipes.noSteps")}</p>
           ) : (
             <ol className="mt-4 space-y-4">
-              {recipe.steps.map((step) => (
+              {displayRecipe.steps.map((step) => (
                 <li key={step.id} className="flex gap-4">
                   <span className="grid h-8 w-8 shrink-0 place-items-center rounded-full bg-brand-600 text-sm font-bold text-white">
                     {step.stepNumber}

meal-plan-frontend/src/i18n/locales/en/translation.json

@@ -161,7 +161,16 @@
     "noIngredients": "No ingredients listed.",
     "noSteps": "No steps listed.",
     "kcal": "{{count}} kcal",
-    "minutes": "{{count}} min"
+    "minutes": "{{count}} min",
+    "recalculateCaloriesTitle": "Adjust calories",
+    "recalculateCaloriesHint": "Enter a target kcal — ingredient amounts will be scaled (catalog + AI).",
+    "targetCalories": "Target kcal",
+    "recalculate": "Recalculate",
+    "applyRecalculation": "Save changes",
+    "recalculatePreview": "Preview: {{previous}} → {{next}} kcal (target: {{target}})",
+    "recalculateUnlinkedHint": "{{count}} ingredient(s) not linked to the catalog — values may be less accurate.",
+    "recalculateCaloriesInvalid": "Enter calories between 50 and 10000 kcal.",
+    "recalculateCaloriesFailed": "Could not recalculate the recipe."
   },
   "manage": {
     "title": "Manage Meals",

meal-plan-frontend/src/i18n/locales/pl/translation.json

@@ -165,7 +165,16 @@
     "noIngredients": "Brak składników.",
     "noSteps": "Brak kroków.",
     "kcal": "{{count}} kcal",
-    "minutes": "{{count}} min"
+    "minutes": "{{count}} min",
+    "recalculateCaloriesTitle": "Dopasuj kaloryczność",
+    "recalculateCaloriesHint": "Podaj docelową liczbę kcal — przeliczymy gramaturę składników (katalog + AI).",
+    "targetCalories": "Docelowe kcal",
+    "recalculate": "Przelicz",
+    "applyRecalculation": "Zapisz zmiany",
+    "recalculatePreview": "Podgląd: {{previous}} → {{next}} kcal (cel: {{target}})",
+    "recalculateUnlinkedHint": "{{count}} składnik(ów) bez powiązania z katalogiem — wartości mogą być mniej dokładne.",
+    "recalculateCaloriesInvalid": "Podaj kaloryczność między 50 a 10000 kcal.",
+    "recalculateCaloriesFailed": "Nie udało się przeliczyć przepisu."
   },
   "manage": {
     "title": "Zarządzaj posiłkami",

meal-plan-frontend/src/pages/RecipeDetailPage.tsx

@@ -1,3 +1,4 @@
+import { useState } from "react";
 import { ArrowLeft } from "lucide-react";
 import { useNavigate, useParams } from "react-router-dom";
 import { useTranslation } from "react-i18next";
@@ -6,13 +7,16 @@ import { RecipeDetail } from "@/components/recipes/RecipeDetail";
 import { Skeleton } from "@/components/ui/Skeleton";
 import { ErrorState } from "@/components/ui/ErrorState";
 import { extractApiError } from "@/api/axiosInstance";
+import type { RecipeDetail as RecipeDetailModel } from "@/types/recipe.types";
 
 export function RecipeDetailPage() {
   const { t } = useTranslation();
   const { id } = useParams<{ id: string }>();
   const navigate = useNavigate();
   const recipeId = Number(id);
-  const { data: recipe, isLoading, isError, error, refetch } = useRecipe(recipeId);
+  const { data: fetchedRecipe, isLoading, isError, error, refetch } = useRecipe(recipeId);
+  const [recipe, setRecipe] = useState<RecipeDetailModel | null>(null);
+  const displayRecipe = recipe ?? fetchedRecipe ?? null;
 
   return (
     <div className="space-y-6">
@@ -41,7 +45,15 @@ export function RecipeDetailPage() {
         />
       )}
 
-      {!isLoading && !isError && recipe && <RecipeDetail recipe={recipe} />}
+      {!isLoading && !isError && displayRecipe && (
+        <RecipeDetail
+          recipe={displayRecipe}
+          onRecipeUpdated={(updated) => {
+            setRecipe(updated);
+            void refetch();
+          }}
+        />
+      )}
     </div>
   );
 }

meal-plan-frontend/src/types/recipe-management.types.ts

@@ -37,3 +37,18 @@ export interface RecipeMacroRecalcResult {
   recipesUpdated: number;
   unlinkedIngredientRows: number;
 }
+
+export interface RecalculateRecipeCaloriesResult {
+  recipeId: number;
+  previousCalories?: number | null;
+  targetCalories: number;
+  newCalories?: number | null;
+  newProtein?: number | null;
+  newFat?: number | null;
+  newCarbs?: number | null;
+  applied: boolean;
+  method: string;
+  unlinkedIngredientCount: number;
+  ingredients: import("./recipe.types").Ingredient[];
+  recipe?: import("./recipe.types").RecipeDetail | null;
+}