Recipe Scaler

Enter recipe ingredients and scale them up or down by serving count with automatic unit conversion.

Tested tool guide Tested browser tools Checked August 16, 2026

What Recipe Scaler does, with a checked example

The Recipe Scaler takes an ingredient list, the servings the recipe makes, and the servings you actually need, then multiplies every amount by the ratio between them. A recipe for 4 scaled to 6 comes out at one-and-a-half times each ingredient, with units tidied along the way: a third of a cup becomes a half cup. What does not scale is the part people forget - cook time, oven temperature, and pan size follow their own rules, and the tool's output is ingredient quantities only.

Worked example

A concrete input and expected output from the current implementation.

Input

1/2 cup rolled oats
2 tbsp brown sugar
serves 2, make 8

Expected output

2 cups rolled oats
1/2 cup brown sugar
serves 8

The ratio of target to original servings is 8/2 = 4, so each amount is multiplied by 4. Half a cup of oats becomes 2 cups, and 2 tablespoons of sugar becomes 8 tablespoons; since 16 tablespoons make a cup, 8 tablespoons is shown as the half cup that is easier to measure.

How the result is produced

Ratio scaling

The operation is one division followed by many multiplications: target servings divided by original servings gives the factor (6 / 4 = 1.5), and every amount is multiplied by it. Fractions and decimals behave the same way - a 1/4 cup at factor 1.5 becomes 3/8 cup. Whole-item counts are scaled arithmetically too, which is how '1 egg' can come out as 1.5 eggs.

Unit tidying

Scaled amounts can be rewritten in larger units within the same family: 3 teaspoons to a tablespoon, 16 tablespoons to a cup, 16 ounces to a pound. These factors are fixed by definition, so the conversion is deterministic. What is not fixed is the mass of a volume such as a cup of flour, which depends on the ingredient and how it was scooped.

Good uses

Doubling a family dinner: a stew written for 4 servings, pasted in with the target set to 8, so every ingredient amount comes back pre-computed.
Halving a large batch: a cookie dough that makes 24 cut down to 12 without dividing six separate amounts by hand.
Scaling a two-person weeknight recipe up to four or six portions for meal prep, so each scaled amount stays measurable with standard spoons and cups.

Limits and checks

Only amounts scale, not cooking. Baking time, oven temperature, and pan size follow their own rules - a doubled loaf takes longer than the original but not twice as long, and a doubled liquid in the same pot can boil over. The output is an ingredient list, not a cooking plan.
Whole items can come out fractional. One egg scaled at 1.5 reads as 1.5 eggs, and half of a single 400 g can of tomatoes is not something you can open. Adjust these by hand: use the nearest whole unit and accept the difference, or split where the ingredient allows.
Volume and weight are separate lanes. Cups, tablespoons, and milliliters convert among themselves, and grams, ounces, and pounds among themselves, but cups to grams needs the ingredient's density: roughly 120 g of all-purpose flour per cup versus roughly 200 g of granulated sugar. Weigh the ingredient once and scale the gram figure when precision matters.

Common questions

Does scaling the recipe change the cooking time?

Scaling recalculates ingredient amounts; it does not touch time or temperature. A doubled casserole usually needs more time, but not double, and the oven setting typically stays the same. Judge by doneness - a clean skewer or an internal temperature - rather than by stretching the original minutes proportionally.

I scaled a recipe for 3 servings up to 5 and got fractions like 1 2/3 cups. Is that right?

Yes. The factor is 5/3, so any amount is multiplied by five and divided by three: 1 cup becomes 1 2/3 cups, and 2 tablespoons becomes 3 1/3 tablespoons. The fractions are exact; measuring them is the awkward part. For forgiving ingredients like stock, rounding to the nearest measurable amount is fine, but keep leavening exact.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.