Scale any recipe up or down by servings and instantly convert one ingredient amount.
Usage Tip
Spices and salt often need slightly less than a straight scale-up; taste as you go.
How recipe scaling works
Scaling a recipe is one multiplication: divide the servings you want by the servings the recipe makes to get a scale factor, then multiply every ingredient by it. Want 12 servings from a recipe for 4? That is a factor of 3, so everything triples. The calculator above does this for a whole ingredient list at once, with fractions kept tidy.
scale factor = servings wanted ÷ servings in recipe
new amount = original amount × scale factor
How to double a recipe
Doubling is a factor of 2 – multiply every ingredient by two. A few things do not quite double: salt, spices and leavening are best increased by a little less than 2× and adjusted to taste, and you will likely need a larger pan and a slightly longer bake. Mixing may also need to be done in batches if your bowl is small.
How to halve a recipe
Halving means multiplying by 0.5. The tricky part is eggs: beat one egg, then use half by weight or volume (about 25 g) for an accurate half. Tiny amounts like “1/4 teaspoon” become awkward – round sensibly to the nearest pinch. A smaller pan and shorter bake time usually follow.
Scaling for a crowd
Large multiples (5×, 10× and up) bring practical limits, not just maths. Watch oven and pan capacity, mix in manageable batches, and remember that seasoning and leavening should be scaled conservatively then tasted. Bake in multiple pans rather than one giant one so heat reaches the centre.
Common scaling chart
| Original | Half | Double | Triple |
|---|---|---|---|
| 1/4 tsp | 1/8 tsp | 1/2 tsp | 3/4 tsp |
| 1/2 tsp | 1/4 tsp | 1 tsp | 1 1/2 tsp |
| 1 tsp | 1/2 tsp | 2 tsp | 1 tbsp |
| 1 tbsp | 1 1/2 tsp | 2 tbsp | 3 tbsp |
| 1/2 cup | 1/4 cup | 1 cup | 1 1/2 cups |
| 1 cup | 1/2 cup | 2 cups | 3 cups |
Scaling fractions and tricky amounts
Scaling rarely lands on neat numbers. The calculator shows tidy fractions (like 2/3 or 1 1/2) instead of long decimals. For amounts that fall between measuring spoons, round to the nearest practical fraction – precision matters far more for baking than for a soup or stew.
Maths is exact, baking is not
Scaling baking ingredients
Flour, sugar, fat and liquid scale cleanly with the factor. The ingredients to watch are the active ones:
Yeast
Scales close to linearly for modest changes, but for big batches you can use slightly less yeast and a longer rise for better flavour.
Baking powder & soda
Scale with the recipe for small changes; at 3× and above, hold back about 10–15% to avoid a soapy taste or over-rise.
Spices and seasoning
Salt, spices, garlic and strong flavourings intensify in larger batches, so scaling them fully can overwhelm a dish. Start at about 75–90% of the scaled amount for big multiples, then taste and adjust upward. It is much easier to add than to remove.
Cooking and baking time
Time does not scale with the recipe. Keep the oven or stove temperature the same and adjust time: a deeper or larger bake takes longer, a thinner or smaller one less. Always test for doneness – a skewer for cakes, internal temperature for roasts – rather than trusting a scaled clock.
Common scaling mistakes
- Scaling salt, spices and leavening fully at large multiples.
- Assuming cooking time scales with the recipe.
- Forgetting to use a bigger (or smaller) pan to match the new volume.
- Rounding eggs up or down instead of measuring half an egg.
- Mixing a huge batch in a bowl that is too small to combine it evenly.
Popular recipe conversions
| From | To | Factor |
|---|---|---|
| 4 servings | 2 servings | × 0.5 |
| 4 servings | 6 servings | × 1.5 |
| 4 servings | 8 servings | × 2 |
| 6 servings | 12 servings | × 2 |
| 8 servings | 24 servings | × 3 |
Scaling for a different pan size
If you are scaling to fit a specific tin rather than a serving count, work from pan volume instead. The Cake Pan Converter gives the batter factor between pan sizes, and the Loaf Pan Size Calculator shows how much a loaf pan holds.