Recipe Scaling Calculator
Enter the recipe’s original servings (e.g. 4) and the number you actually want to cook (e.g. 8) — every ingredient with an amount is scaled in proportion and snapped to friendly kitchen fractions (½ cup, ¼ tsp) or sensible round grams/ml. Lines without a number (like “Salt to taste”) are left untouched so you can paste the whole list straight back into your notes.
Both servings must be positive numbers.
Tip: tiny amounts (e.g. 1/8 tsp salt) are best fine-tuned by taste. Baking is ratio-sensitive — the larger the scale, the more visible small errors become.
Formula
Scale factor k = target servings / original servings For every ingredient: new_amount = original_amount × k Volume units (cup, tbsp, tsp) snap to common kitchen fractions (1/8, 1/4, 1/3, 1/2, 2/3, 3/4, 7/8). Grams and millilitres use smart rounding (1 / 5 / 10 / 50 depending on magnitude). Count units (eggs, cloves, slices) pluralise automatically and round to a nearby integer where possible.
- · The parser recognises common English units: cup, tbsp, tsp, ml, l, g, kg, oz, lb, fl oz, pinch, dash, clove, slice, can, package, piece, stick — along with their singular/plural forms and standard abbreviations.
- · Amounts can be written as integers (2), decimals (0.25), fractions (1/2) or mixed numbers (1 1/2).
- · Volume units (cup, tbsp, tsp) snap to the closest of 1/8, 1/4, 1/3, 1/2, 2/3, 3/4, 7/8. If the deviation exceeds 5 %, the tool falls back to a 2-decimal number.
- · Grams and millilitres use magnitude-aware rounding: < 1 keeps 2 decimals; 1–10 uses 1 decimal; 10–100 uses the nearest integer; 100–500 rounds to the nearest 5; 500–2000 rounds to the nearest 10; above that, the nearest 50.
- · Count units (eggs, cloves, slices) pluralise automatically and round to the nearest quarter so you don’t end up with “2.367 eggs”.
- · Baking is ratio-sensitive: when you scale a recipe by more than ~3×, double-check salt, yeast and baking powder — small absolute differences become noticeable.
- · References: King Arthur Baking Ingredient Weight Chart; NIST Handbook 44 definitions of household kitchen measures.
Frequently asked
Why does 1/3 cup × 2 show as 2/3 cup instead of 0.667 cup?
Kitchen measuring cups and spoons only come in specific fractional sizes (1/4, 1/3, 1/2, 2/3, 3/4 …). Showing fractions means you can grab the right cup straight from the drawer. The tool snaps the computed amount to the closest common kitchen fraction whenever the deviation is under ~5 %. If the snap would be misleading (say a result far from any standard cup size), it falls back to a decimal instead.
Can I shrink a recipe down to a single serving?
Absolutely — set the target servings to 1 (e.g. 4 → 1 gives a ×0.25 scale). Two caveats: (1) in baking, tiny amounts of salt / baking powder / yeast become hard to measure accurately — use a precision spoon set or a 0.01 g scale; (2) some techniques have a minimum batch size (e.g. whipping egg whites with less than one egg simply doesn’t work).
What happens to lines without a number, like “Salt to taste”?
Lines without a leading number are passed through verbatim, so you can copy the whole scaled list back into your notes. The rule is simple: a line is considered “scaleable” only if it starts with a number (1, 1.5, 1/2, 1 1/2 etc.). Lines like “Salt to taste” or “Black pepper, freshly ground” are left exactly as you typed them.
My recipe is in grams and millilitres — does this work?
Yes — and metric (grams / millilitres) is usually more accurate than cups, especially for baking. Enter lines like “250 g flour” or “180 ml milk” and the tool will scale and then round to a magnitude-aware step (decimals for small amounts; multiples of 5, 10, or 50 for larger ones) so the figure is easy to read off your kitchen scale.
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