Recipe Scaler Calculator
Scale a recipe up or down by servings, with each ingredient rounded to real measuring-spoon fractions — and a straight answer on what doesn't scale.
Recipe Scaler Calculator: with the default inputs, scale factor is 1.5.
Multiply every ingredient by this.
- Ingredient 1
- 3 cups
- Ingredient 2
- 2 ¼ tsp
- Ingredient 3
- ¾ tsp
- Ingredient 4
- 1 ⅞ cups
- Ingredient 5
- 3
- Ingredient 6
- 4 ½ tbsp
- Pan dimension factor
- 1.22√scale — multiply the length and width of the pan by this, not the scale itself.
Assumptions
- Ingredient amounts scale linearly; the calculator does not adjust leavening, salt or spices for you.
- Spoon and cup amounts are rounded to the nearest eighth (tablespoons to the nearest quarter, whole items to the nearest half).
- Pan dimensions scale by the square root of the scale factor, which keeps depth — and therefore cooking time — roughly constant.
- US customary volume measures: 1 cup = 16 tablespoons = 48 teaspoons = 8 fl oz = 236.6 mL.
| Ingredient | Original | Scaled ×1.5 | Exact (unrounded) |
|---|---|---|---|
| Ingredient 1 | 2 cups | 3 cups | 3 |
| Ingredient 2 | 1 ½ tsp | 2 ¼ tsp | 2.25 |
| Ingredient 3 | ½ tsp | ¾ tsp | 0.75 |
| Ingredient 4 | 1 ¼ cups | 1 ⅞ cups | 1.875 |
| Ingredient 5 | 2 | 3 | 3 |
| Ingredient 6 | 3 tbsp | 4 ½ tbsp | 4.5 |
Spoon and cup amounts are rounded to the nearest eighth (quarter for tablespoons); the exact column is what the arithmetic gives.
| Amount | Is also |
|---|---|
| 1 tablespoon | 3 teaspoons |
| 1/4 cup | 4 tablespoons = 12 teaspoons |
| 1/3 cup | 5 tablespoons + 1 teaspoon |
| 1/2 cup | 8 tablespoons = 4 fl oz |
| 3/4 cup | 12 tablespoons = 6 fl oz |
| 1 cup | 16 tablespoons = 8 fl oz = 237 mL |
| 1 large egg | about 50 g out of the shell (30 g white, 20 g yolk) |
| 1 stick of butter | 1/2 cup = 8 tablespoons = 113 g |
When a scaled amount lands somewhere unmeasurable, convert down to teaspoons or across to grams.
How this is worked out
The formula
Scale factor = desired servings ÷ original servings Scaled amount = original amount × scale factor Pan dimension factor = √(scale factor) — area scales with the recipe, sides scale with its square root
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Recipe serves
- A number.from 0.25 to 1000 · defaults to 4
- You want to serve
- A number.from 0 to 1000 · defaults to 6
- Ingredient 1 — amount
- A number.0 or more · defaults to 2
- Ingredient 1 — unit
- Choose one of 11 options.cups · tablespoons · teaspoons · fluid ounces · millilitres · litres · grams · kilograms · ounces (weight) · pounds · whole items (eggs, cloves…)
- Ingredient 2 — amount
- A number.0 or more · defaults to 1.5
- Ingredient 2 — unit
- Choose one of 11 options.cups · tablespoons · teaspoons · fluid ounces · millilitres · litres · grams · kilograms · ounces (weight) · pounds · whole items (eggs, cloves…)
- Ingredient 3 — amount
- A number.0 or more · defaults to 0.5
- Ingredient 3 — unit
- Choose one of 11 options.cups · tablespoons · teaspoons · fluid ounces · millilitres · litres · grams · kilograms · ounces (weight) · pounds · whole items (eggs, cloves…)
- Ingredient 4 — amount
- A number.0 or more · defaults to 1.25
- Ingredient 4 — unit
- Choose one of 11 options.cups · tablespoons · teaspoons · fluid ounces · millilitres · litres · grams · kilograms · ounces (weight) · pounds · whole items (eggs, cloves…)
- Ingredient 5 — amount(under More options)
- A number.0 or more · defaults to 2
- Ingredient 5 — unit(under More options)
- Choose one of 11 options.cups · tablespoons · teaspoons · fluid ounces · millilitres · litres · grams · kilograms · ounces (weight) · pounds · whole items (eggs, cloves…)
- Ingredient 6 — amount(under More options)
- A number.0 or more · defaults to 3
- Ingredient 6 — unit(under More options)
- Choose one of 11 options.cups · tablespoons · teaspoons · fluid ounces · millilitres · litres · grams · kilograms · ounces (weight) · pounds · whole items (eggs, cloves…)
What you get back
- Scale factormain answer
- Multiply every ingredient by this.
- Ingredient 1
- Ingredient 2
- Ingredient 3
- Ingredient 4
- Ingredient 5
- Ingredient 6
- Pan dimension factor
- √scale — multiply the length and width of the pan by this, not the scale itself.
What this assumes
- Ingredient amounts scale linearly; the calculator does not adjust leavening, salt or spices for you.
- Spoon and cup amounts are rounded to the nearest eighth (tablespoons to the nearest quarter, whole items to the nearest half).
- Pan dimensions scale by the square root of the scale factor, which keeps depth — and therefore cooking time — roughly constant.
- US customary volume measures: 1 cup = 16 tablespoons = 48 teaspoons = 8 fl oz = 236.6 mL.
About this calculator
Scaling a recipe is multiplication, and the multiplication is the easy part. What this calculator adds is the rounding — turning 1.875 cups into "1 ⅞ cups" instead of a number you can't measure — and a clear list of the things that do not scale, which is where doubled recipes actually go wrong.
How to use it
Enter what the recipe serves now and what you want it to serve. Put up to six ingredients in with their units; ingredients five and six are under More options. Spoon and cup amounts come back as fractions rounded to the nearest eighth (nearest quarter for tablespoons), weights come back as decimals, and whole items round to the nearest half so you can see when you're being asked for one and a half eggs.
What does not scale linearly
This is the useful half of the answer.
- Baking and cooking time. Time follows the depth of the food and how fast heat reaches the middle, not its volume. A doubled cake batter in a bigger pan of the same depth takes roughly the same time. The same batter poured twice as deep takes far longer and burns at the edges first. Check for doneness at the original time and then every five minutes.
- Pan size. Area should scale with the recipe, so each side scales by the square root. Doubling means ×1.41 on each dimension: an 8-inch round becomes an 11-inch, not a 16-inch. The calculator gives you the factor.
- Leavening. Baking powder and baking soda do not double cleanly. Above about 2× use roughly 75–80% of the linear amount, or you get a coarse crumb, a domed then collapsed top, and a soapy taste. Yeast scales even less: at 2× dough, use about 1.5× the yeast and watch the dough, not the clock.
- Salt and strong spices. Salt scales close to linearly in a braise or a soup, but cayenne, cloves, cinnamon, nutmeg and bay compound. Take them to about 75% and correct at the end — you can always add.
- Alcohol, extracts and acid. Vanilla, wine and vinegar concentrate as they reduce. Scale to 75% and taste.
- Evaporation and browning. A doubled sauce in the same pan has the same surface area, so it reduces at the same rate but from twice the volume — it takes much longer than double the time. A wider pan fixes it; a taller one doesn't.
Halving
Going down has its own problems. Half an egg is real: beat one and weigh out half (about 25 g). A quarter teaspoon of yeast or soda is at the limit of what a measuring spoon does honestly — weigh it if you own a scale that reads to 0.1 g. And a half batch in the original pan is too thin, so drop a pan size.
Frequently asked questions
▸How do I double a recipe?
Multiply every ingredient by two, then pull back the leavening to about 1.6–1.75× and the strong spices to about 1.5×. Use a pan with twice the area — √2 = 1.41 on each side — and check for doneness at the original time.
▸Does baking time double when I double a recipe?
No. Time depends on how deep the food is, not how much of it there is. Keep the depth the same by using a bigger pan and the time barely changes; double the depth and it can take half again as long, with burnt edges.
▸What pan should I use for a scaled recipe?
Scale the linear dimensions by the square root of the scale factor. An 8-inch round doubled becomes about 11 inches; a 9 × 13 halved becomes about 6 × 9. Keeping the depth constant is what keeps the cooking time constant.
▸How do I measure half an egg?
Crack one, beat it, and use half by weight — a large egg is about 50 g out of the shell, so 25 g. For thirds, the same trick with a scale. Never try to halve it in the shell.
▸Why shouldn't I just double the salt and spices?
Salt in a soup or braise is close to linear, but the volatile spices — cayenne, clove, cinnamon, nutmeg — build much faster than the other flavours around them. Start at about 75%, taste at the end, and add. You cannot take them back out.
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