Recipe Scaler

Enter how many servings the recipe makes, how many you actually need, and your ingredients. You will get each amount rescaled and rounded to a measurement you can actually read off a measuring cup, not a decimal you need a calculator to use.

Enter up to 8 ingredients. Amounts accept fractions and mixed numbers ("1 1/2", "3/4", "2"). Leave unused rows blank.

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How the recipe scaler works

Every recipe is built around a scale factor: your desired servings divided by the original servings. Multiply every ingredient by that factor and, in theory, you get a perfectly resized recipe. In practice, kitchen measuring tools do not offer infinite precision, and a few ingredients do not scale like the rest. This tool does the multiplication, then rounds each amount to a fraction you can actually measure (whole, 3/4, 2/3, 1/2, 1/3, 1/4, 1/8 cup or teaspoon), and flags the ingredients that need a different kind of thinking.

The formula

Scale factor = Desired servings ÷ Original servings

Every ingredient amount is then multiplied by that same factor, then rounded to the nearest practical kitchen fraction.

Worked example

A recipe serves 4 and calls for 1 1/2 cups flour. You want 6 servings:

Scale factor = 6 ÷ 4 = 1.5, shown as x 1 1/2.

Flour = 1 1/2 cups × 1 1/2 = 2.25 cups = 2 1/4 cups (this one lands exactly on a measurable fraction, no rounding gap).

What does not scale like the rest (read this before you multiply everything)

Straight multiplication is a fine starting point, but a few categories of ingredient and a couple of physical realities do not behave linearly. This is the part most recipe-scaling tools skip, and it is usually the difference between a scaled recipe that works and one that quietly fails.

Eggs come in whole units, not fractions. You cannot crack 1.5 eggs. Weigh instead: 1 large egg is about 50 g of beaten egg, so 1.5 eggs is 75 g. Crack the eggs you need into a bowl, beat them together, and pour out the weighed portion. This calculator does that math for you automatically whenever an ingredient name contains "egg."

Salt and spices scale at about 75 percent when you double a recipe. Your palate does not perceive saltiness or spice heat on the same linear curve that volume scales on, so a straight doubling routinely oversalts or overspices a dish. Start around 75 percent of the linearly scaled amount, taste, and add more from there. Season to taste always wins over the math.

Baking soda and baking powder slightly under-scale on big multiples. Triple or quadruple a recipe and a full linear scale-up of the leavening can leave a bitter, soapy taste and an overly coarse, holey crumb. For anything beyond a double batch, start around 85 to 90 percent of the scaled amount.

Cooking time does not scale with quantity. A double batch of cookies on a tray bakes in the same time as a single batch, because each cookie is still the same thickness and heat still travels the same distance into it. A doubled roast in one bigger piece of meat takes longer, because the heat now has farther to travel to reach the center. Quantity is not the variable that drives time; thickness and mass per piece are. Use a thermometer or toothpick rather than trusting a scaled clock.

Pan area matters more than serving count. If you are also changing pans as you scale servings, the batter's depth in the pan depends on area, not on how many servings the recipe claims. Two pans can hold very different amounts of batter for a "similar" size. Check your new pan against your old one with the pan size converter before you assume a scaled recipe will bake the same way.

For ingredient amounts given by weight rather than volume, cups to grams and the butter converter handle the unit conversion; for odd measurement terms in an old recipe, try the cooking measurement converter.

Frequently asked questions

How do I halve a recipe with 3 eggs?

Weigh it instead of splitting the shell: 1 large egg is about 50 g of beaten egg, so half of 3 eggs is 75 g. Crack all 3 eggs into a bowl, beat them together, weigh out 75 g, and use the rest for something else (an omelet, a wash for pastry). This calculator does this math for you automatically when it spots an egg row.

Why does my scaled amount show a decimal next to a fraction, like "2/3 cup, exactly 0.700"?

Because kitchen measuring cups only come in a few sizes (1, 3/4, 2/3, 1/2, 1/3, 1/4, 1/8), your exact scaled amount often does not land on one of them. We round to the nearest cup size you can actually measure, and show the true decimal alongside so you know how much rounding happened. When the gap is tiny, use the fraction and stop worrying about it.

Does scaling a recipe up or down change the cooking time?

No, and this trips people up constantly. Cooking time depends on how heat travels through the food, not on the total quantity. A double batch of cookies on the same tray bakes in the same time as a single batch (same thickness per cookie). A doubled roast in one larger piece takes longer because heat has farther to travel to the center. Check doneness with a thermometer or toothpick rather than trusting a scaled-up clock.

Should I double the salt and spices when I double a recipe?

Not quite. Salt and spices scale at roughly 75 percent when you double a recipe, then you adjust to taste. Doubling every seasoning exactly tends to oversalt or overspice the dish because your palate does not perceive flavor linearly the way volume scales. Start at 75 percent of the doubled amount, taste, and add more if it needs it.

What about baking soda and baking powder when I scale up a lot?

Leaveners slightly under-scale at large multiples (tripling or more). Too much baking soda or powder can leave a bitter, soapy taste and an overly open, coarse crumb. For anything past a double batch, start around 85 to 90 percent of the linearly scaled amount and adjust in your next attempt based on how the crumb and flavor turn out.

Can I just scale a recipe to fit a different pan size?

Scaling ingredients and matching the pan are two different problems, and pan area does not always track serving count the way you would expect. Use the pan size converter to compare your original pan's area to your new pan's area; that ratio, not the serving count, tells you how much batter volume and how much extra bake time you actually need.

Why is the scale factor shown as a fraction like "x 1 1/2" instead of 1.5?

Because that is how you will actually use it standing at the counter with a measuring cup, not a calculator. Whenever the ratio between your original and desired servings lands on a common kitchen fraction (halves, thirds, quarters, eighths), we show it that way. When it does not land cleanly, we fall back to a decimal.

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