Recipe Scaler (Serving Size Converter)

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.

Scale Factor
x
Multiply every ingredient by this
THE MATH
factor = desired servings ÷ original servings
Multiply each ingredient by the scale factor to keep proportions correct.
Cooking times and pan sizes do not scale linearly – check doneness when scaling up.

See it in action

Original recipe

Serves 4

  • 2 cups flour
  • 1 cup milk
  • 2 eggs
  • 1 tsp salt

Scaled recipe× 2

Serves 8

  • 4 cups flour
  • 2 cups milk
  • 4 eggs
  • 2 tsp salt

Going from 4 to 8 servings is a scale factor of 2, so every ingredient simply doubles. Enter your own serving numbers above to get the factor for any recipe.

How recipe scaling works

Divide the servings you want by the servings the recipe makes to get one scale factor, then multiply every ingredient by it. Four to six servings is ×1.5; doubling is ×2; halving is ×0.5. The arithmetic is exact for ingredients – but a few things do not move on the same straight line.

What does not scale linearly: cooking and baking time, pan size, and oven temperature. Salt, spices, and leavening (baking powder, soda, yeast) usually need a little less than the exact multiple when you scale up. Scale the ingredients, then use judgment on these.

Popular scaling examples

Double a recipe

Multiply every ingredient by 2. Keep the oven temperature the same and check doneness a little later.

Halve a recipe

Multiply by 0.5. For one egg, beat it and use half by weight, about 25 g.

4 to 6 servings

Multiply by 1.5 – every quantity goes up by half.

6 to 12 servings

Multiply by 2 – a straight double of the recipe.

4 to 8 servings

Multiply by 2; you may need a larger pan or two pans.

Scale for a crowd

Divide your target by the original servings; for big batches ease back on salt and strong spices.

Common scaling table

OriginalDoubleHalf
1/4 tsp1/2 tsp1/8 tsp
1/2 tsp1 tsp1/4 tsp
1 tsp2 tsp1/2 tsp
1 tbsp2 tbsp1 1/2 tsp
1/4 cup1/2 cup2 tbsp
1/2 cup1 cup1/4 cup
1 cup2 cups1/2 cup
2 cups4 cups1 cup

Scaling fractions and tricky amounts

Halving or multiplying odd fractions is where recipes get fiddly. Use the calculator for the factor, then this chart to land on a clean measure.

Amount× 0.5× 1.5× 2× 3
1/4 cup2 tbsp6 tbsp1/2 cup3/4 cup
1/3 cup2 tbsp + 2 tsp1/2 cup2/3 cup1 cup
1/2 cup1/4 cup3/4 cup1 cup1 1/2 cups
2/3 cup1/3 cup1 cup1 1/3 cups2 cups
3/4 cup6 tbsp1 1/8 cups1 1/2 cups2 1/4 cups

Scaling for a different pan size

Changing pan size too?Pan area, not just servings, decides batter volume and bake time.Cake Pan Converter →

When you change pan size, scale the batter by the change in pan area, and expect the bake time to shift because the batter sits at a different depth.

Pan changeArea changeMultiply batter by
8" round → 9" round+26%× 1.26
9" round → 10" round+23%× 1.23
8" round → 10" round+56%× 1.56
8×8 square → 9×13+83%× 1.83
9×13 → 8×8 square−45%× 0.55

Recipe scaling tips

Scales easily

  • Flour
  • Sugar
  • Milk and water
  • Oil and most liquids
  • Dry staples by weight

May need adjustment

  • Salt
  • Baking powder and soda
  • Yeast
  • Strong spices
  • Alcohol and extracts

When scaling up, start with slightly less salt, leavening, and spice than the exact multiple, then adjust to taste. When scaling down, leavening can be hard to measure accurately – weigh it if you can.

Popular recipe conversions

Double a cookie recipe

Multiply each ingredient by 2 and bake in batches so the trays are not overcrowded.

Half a cake recipe

Multiply by 0.5 and drop to a smaller pan so depth and bake time stay close to the original.

Triple a chili recipe

Multiply by 3, but hold back on the chili and salt, then taste and adjust at the end.

Scale soup for 20

Plan about 350 ml per person as a main, multiply, and use a pot big enough to stir comfortably.

Frequently asked questions

Does cooking time scale with quantity?No. Time depends on pan size and how deep the food sits, not the total volume. Check for doneness instead of multiplying the time.
How do I scale a recipe that uses eggs?Beat one egg and use half by weight (about 25 g) for a half egg, or scale to a factor that lands on whole eggs.
Should I scale salt and spices exactly?Scale them as a starting point, then taste. Seasoning often needs slightly less than the exact multiple when scaling up.
Can I scale baking recipes freely?Baking is sensitive to ratios and pan depth. Scale by simple factors, keep the pan depth similar, and expect to adjust the bake time.

Popular cooking converters

Note: The scale factor is exact arithmetic, but cooking and baking times, pan sizes, leavening, and seasoning may need adjustment by judgment – especially for baking. Scale ingredients with the calculator, then taste and watch for doneness.
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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.