Recipe serving calculator

How it works

• The factor is servings to make ÷ original servings. Every ingredient quantity is multiplied by the same factor.
• Calculations are exact (as fractions) and only rounded for display, to 2 decimal places. Values changed by rounding are marked with ≈.
• When the result has a denominator of 2, 3, 4 or 8, a fraction such as 1 1/4 is shown too, to make measuring with spoons and cups easier.
• Things that are hard to split, such as eggs, are not rounded to whole numbers. The exact value (for example 1.5) is shown so you can decide.

Entering quantities

• Use decimals (250, 0.5), fractions (1/2), mixed numbers (1 1/2) or fraction characters (½, 1½). Full-width digits work too.
• Choose the decimal mark and thousands separator under “Number format”; it does not depend on the page language. Numbers that don’t match the chosen format (for example “1.5” with a decimal comma) are shown as errors rather than guessed.
• Quantities that aren’t numbers, such as “to taste”, “a pinch” or “1-2”, are kept as they are and marked “Kept”.
• A fraction with 0 below the line (1/0) can’t be calculated and is shown as an error. Servings must be greater than 0.

What is not converted

• Units stay as you typed them. Units are not converted into each other (for example g to cups), because the density of each ingredient isn’t known.
• Cooking times and temperatures are not scaled. Larger amounts may need a different time or pan size.
• No nutritional or allergy judgements are made.

Limits

Up to 50 ingredients and 10,000 servings. Numbers can have 7 whole digits and 4 decimals; fractions up to 4 digits on each side. Everything is calculated on this device and nothing is saved or sent (only the number format setting is remembered).