Recipe scaler

Recipe Scaler & Substitutions

Quick start

1. Get the recipe (user pastes it or describes it).
2. Get the target serving count (or the ingredient they're missing).
3. Scale or substitute, then note any technique adjustments.

Scaling a recipe

Steps

1. Identify original serving count.
2. Compute multiplier: target ÷ original.
3. Scale every ingredient by the multiplier.
4. Apply technique adjustments (see below).

Ingredient table format

Ingredient	Original	× Multiplier	Scaled
flour	2 cups	× 2.5	5 cups
eggs	2	× 2.5	5
butter	100 g	× 2.5	250 g

Round to the nearest practical unit (e.g. 2.5 tsp not 2.47 tsp). Flag when an ingredient doesn't scale linearly (salt, leavening, spices).

Technique adjustments

Factor	Rule
Baking time	Same temperature; check doneness 10–15 % earlier when scaling down, allow extra time when scaling up. Toothpick/internal-temp test beats the clock.
Pan size	Doubling a recipe ≠ doubling pan area. Suggest equivalent pan (e.g. two 9″ rounds instead of one 18″).
Salt & spices	Start at 75 % of scaled amount; taste and adjust. Avoid linear scaling for strong spices (cayenne, fish sauce).
Leavening	Scale at ~75 % when multiplier > 3×; too much baking powder causes collapse.
Cooking fat	Can reduce slightly when scaling up; pans retain more residual heat.

Substitutions

Format

Missing: [ingredient] Substitutes:

1. [Best sub] — [ratio] — [caveat]
2. [Second option] — [ratio] — [caveat]

Common substitutions

Missing	Sub	Ratio	Notes
Buttermilk (1 cup)	Milk + 1 tbsp white vinegar	1:1	Let sit 5 min to curdle
Buttermilk (1 cup)	Plain yogurt thinned with milk	1:1	Works well in baking
Eggs (1 large)	Flax egg (1 tbsp ground flax + 3 tbsp water)	1:1	Vegan; best in muffins/pancakes
Eggs (1 large)	¼ cup unsweetened applesauce	1:1	Adds slight sweetness
Butter (1 cup)	Neutral oil	¾ cup oil	Texture slightly denser
Butter (1 cup)	Coconut oil (solid)	1:1	Adds faint coconut flavour
All-purpose flour (1 cup)	Bread flour	1:1	Chewier result
All-purpose flour (1 cup)	Cake flour	1 cup + 2 tbsp	Lighter, more tender
All-purpose flour (1 cup)	GF blend	1:1	Add ¼ tsp xanthan if blend lacks it
Heavy cream (1 cup)	Whole milk + 1 tbsp butter	1:1	Lower fat; won't whip
Sour cream (1 cup)	Plain Greek yogurt	1:1	Works in most baking and dips
Brown sugar (1 cup)	White sugar + 1 tbsp molasses	1:1	Mix well
Baking powder (1 tsp)	¼ tsp baking soda + ½ tsp cream of tartar	1:1	Use immediately
Fresh herbs (1 tbsp)	Dried herbs	1 tsp	Dried is more concentrated

Output format

## Scaled recipe: [Name] — [original] → [target] servings

**Multiplier:** [n]×

### Ingredients

| Ingredient | Original | Scaled |
|------------|----------|--------|
| … | … | … |

### Technique notes

- [Any pan, time, or leavening adjustments]

---

## Substitutions

**Missing:** [ingredient]
1. [Sub 1] — [ratio] — [caveat]
2. [Sub 2] — [ratio] — [caveat]

Example

Input: Pasta carbonara for 4 → scale to 10 servings.

Multiplier: 10 ÷ 4 = 2.5×

Ingredients

Ingredient	Original	Scaled
Spaghetti	400 g	1 kg
Eggs	4	10
Guanciale / pancetta	150 g	375 g
Pecorino Romano	80 g	200 g
Black pepper	1 tsp	2 tsp (taste first)
Salt (pasta water)	1 tbsp	2 tbsp

Technique notes

• Cook pasta in two large pots to maintain a rolling boil.
• Work in batches when tossing off heat — carbonara seizes if the pan cools too fast.
• Salt at 75 % of scaled amount and adjust.