Recipe Scaler

Why straight math doesn't always scale recipes

Most ingredients in a recipe scale linearly — if you double the servings, you double the flour. But several categories break this rule: spices, leavening agents, eggs (when scaling fractionally), and cooking time. Get any of these wrong and the recipe fails. This scaler does the math; the notes below tell you when to override it.

Spices, salt, and herbs scale at 75-80%

Doubling a recipe rarely needs double the salt or spices. Use these adjustments:

2× scaling: Use 1.5-1.75× the spice/salt amount
3× scaling: Use 2-2.5× the spice amount
4× and up: Use 2.5-3× and taste-adjust at the end

This applies especially to dried herbs, cayenne, chili powder, garam masala, and salt. Fresh herbs scale closer to linear, but still under-add and adjust at the end.

Leavening (baking powder, baking soda)

Linear scaling works up to 1.5×. Past that, scale at 80-90% — too much leavening and your baked goods will rise too fast, collapse, or taste metallic. For halving: keep proportions exact but consider that very small leavening amounts (under 1/4 tsp) are hard to measure accurately.

Eggs are the messiest scaling variable

Doubling: 3 eggs becomes 6. Easy.
Halving: 3 eggs becomes 1.5. Whisk one egg, weigh it (≈50g), use half.
Scaling by 1.5x: 2 eggs becomes 3. 3 eggs becomes 4.5 (use 4 + 1 extra yolk for richness).
Custards/curds: Scale by weight, not count — egg sizes vary 15-20% between "large" and "extra large."

Pan size matters more than oven time

Doubling brownies and using the same 8×8 pan? Disaster. Pan surface area must scale proportionally. Use these substitutions:

8×8 (64 sq in): 1× recipe
9×9 (81 sq in): 1.25×
9×13 (117 sq in): ~1.8× — close to 2× for most batters
Half-sheet (12×18 = 216 sq in): ~3.4×
Two 8×8 pans: Perfect 2× for cakes, brownies, anything that bakes uniformly

Cooking time does NOT scale linearly

Bigger batches need more time, not double time. Rough multipliers:

Stovetop sauté/sear (more food in same pan): +20-30% time, lower heat to compensate.
Roasting (bigger pan, deeper bed): +25-40% time. Stir/rotate halfway.
Baking cakes/breads: Bake time per pan is almost identical if pan depth is the same. A 9×13 isn't significantly longer than two 8×8s.
Stews/braises: Time barely scales — the limiting factor is the toughness of the meat, not volume.

When in doubt, weigh ingredients

Volume measures (cups, tbsp) are inaccurate at scale — packed brown sugar can vary by 30%. Switch to a kitchen scale for any recipe you'll cook multiple times. A flour cup is "supposed to be" 125g, but in real kitchens it ranges from 110g to 165g depending on how it's scooped.