Recipe Scaler Calculator

How it is calculated

The tool scales one ingredient at a time. You enter the servings the recipe was written for, the servings you want, and the amount of one ingredient in any unit. It first finds the scaling factor, factor = desired servings ÷ original servings, then new amount = amount × factor. The new amount and the factor are shown with two decimals, and the amount stays in whatever unit you typed, because the tool does not convert between grams, cups or spoons. Original and desired servings must be above zero and the amount cannot be negative; otherwise there is no result. Repeat the calculation for each ingredient. Scaling is a straight proportion, so it suits flour, vegetables or meat, but salt, spices, raising agents, pan size and cooking time often need judgement beyond the ratio.

Common mistakes

• Entering servings per person or per portion in the servings fields. They take the total servings of the original recipe and of the batch you want.
• Scaling spices, salt and raising agents by the full factor. Large batches often need less than the straight proportion, so taste and adjust.
• Assuming cooking time and pan size scale the same way. Doubling a cake does not double the baking time.
• Mixing units between runs, such as grams for one ingredient and cups for another, then reading them as one list. The unit stays as you typed it.
• Using a result such as 166.67 as it stands instead of rounding to the closest amount you can actually measure.