How to scale a recipe up or down
Doubling a recipe sounds like multiplying every number by two. That works for flour, sugar, milk and eggs. It does not work for the pan, the oven time, the salt, or the baking powder — and those are the things that decide whether the doubled version tastes like the original.
What scales linearly
For this group, our recipe scaler handles the arithmetic and rounds to fractions you can actually measure — 1 ⅓ cups rather than 1.3333 cups.
- Flours, sugars and starches — multiply directly.
- Liquids: milk, water, stock, oil, cream.
- Fats: butter, shortening, oils.
- Main proteins and vegetables.
- Chocolate, nuts, dried fruit and other add-ins.
What does not scale linearly
| Ingredient | Scale by | Why |
|---|---|---|
| Baking powder / soda | 1.5x, then taste | Too much leavener causes a soapy flavour and collapse. |
| Salt | 1.5-1.75x | Perceived saltiness rises faster than the amount. |
| Yeast | 1.5x | More dough means more self-generated warmth and faster rise. |
| Strong spices, garlic, chilli | 1.5x, then adjust | Aromatics intensify disproportionately. |
| Alcohol, vanilla, extracts | 1.5x | Volatiles concentrate as they cook off less. |
| Thickeners (cornstarch, roux) | 1.5-1.75x | Depends on surface area and evaporation, not volume. |
Eggs: the awkward one
Halving a recipe with three eggs leaves you needing one and a half. Crack the eggs into a bowl, beat them lightly, weigh the total, and use half the weight. A large egg out of shell is about 50 g — roughly 30 g white and 20 g yolk.
For a recipe needing 1.5 eggs, that is about 75 g of beaten egg. This is far more accurate than guessing.
Pans and bake times
The pan has to grow with the batter, and pan area does not grow the way you expect. Doubling a recipe does not mean doubling the pan diameter — a 12-inch round has more than twice the area of an 8-inch round.
Aim for the same batter depth as the original. If the depth is the same, the bake time is close to the original. If the layer is deeper, lower the oven by about 25°F / 15°C and extend the time, checking early and often.
- Same depth, bigger footprint: time stays similar.
- Deeper batter: reduce temperature, increase time.
- Split across two pans instead of one deep one whenever you can.
- Start checking at 60% of the original time when scaling up.
Practical limits
Scaling beyond about 3x tends to break down. Mixers overflow, pans do not fit, evaporation rates change, and browning becomes uneven. For large batches it is more reliable to run the original recipe multiple times.
Scaling below about 0.25x runs into the opposite problem: quantities become too small to measure, and thin batters in oversized pans burn at the edges.
Frequently asked questions
Can I just double everything?
Double the bulk ingredients, but hold leaveners, salt and strong spices back to about 1.5x and adjust to taste. Also check that your pan and oven can handle the larger volume.
How do I halve an egg?
Beat the egg, weigh it, and use half the weight. One large egg is roughly 50 g, so half is about 25 g.
Does bake time double when the recipe doubles?
No. If you keep the batter depth the same by using a larger or second pan, the time barely changes. Only deeper batter needs meaningfully longer, at a slightly lower temperature.
Should I scale yeast the same as flour?
Use about 1.5x rather than 2x. A larger dough mass retains more of its own heat and ferments faster, so proportionally less yeast is needed.