About this tool

Recipe Scaler & Serving Converter

Scale any recipe up or down by servings or pan size, with fraction-friendly amounts and smart tips for salt, spice, and leavening.

Recipe Scaler multiplies every ingredient in a recipe by one factor, worked out either from servings (target ÷ original) or from baking pan area, and rewrites the results as kitchen-friendly fractions instead of decimals. Pan mode uses real area maths — π × (diameter ÷ 2)² for round tins, side² for square — so moving an 8-inch round to a 9-inch round comes out at 1.27x, not 1.13x. It also flags the ingredients that should not be scaled linearly: leavening, salt, spices and eggs each get their own advisory instead of a blind multiplication.

How to use Recipe Scaler & Serving Converter

1. 1

   Open Recipe Scaler & Serving Converter on AltFTool — it loads instantly in your browser.

2. 2

   Build the ingredient list with Add row, or open Paste list, drop the recipe into Paste ingredients — one per line and press Parse & add; it reads 1/2, half-symbol fractions and 1 1/2 alongside cups, tbsp, tsp, g and ml.

3. 3

   Pick By servings and set Original servings and Target servings, using the Half it, x1.5, Double and Triple chips, or pick By pan size and set the Original pan and Target pan, which scales on area rather than diameter.

4. 4

   Scale factor shows the multiplier, the Scaled recipe list rewrites every amount as a cook-friendly fraction, and Watch-outs for this scale flags salt, spices, leavening and eggs; Copy recipe copies the list and Download saves scaled-recipe.txt.

Why use Recipe Scaler & Serving Converter

• Fractions a cook can actually measure

  Scaled amounts snap to 1/8, 1/6, 1/4, 1/3, 3/8, 1/2, 5/8, 2/3, 3/4, 5/6 or 7/8 within a 0.03 tolerance, falling back to a decimal only when nothing fits.

• Pan conversion by area, not diameter

  Round, square and rectangular tins in inches or centimetres, with presets, so tin swaps use the ratio that actually governs batter depth.

• Warns where linear scaling fails

  Leavening, salt and salty sauces, spices and extracts, and eggs are detected by name and each carries its own adjustment note.

Common use cases

• A recipe serves 4, eight people are coming, and you want the whole ingredient list rewritten at 2x with the amounts still readable as 1 1/2 tsp rather than 1.5.
• You own a 9-inch tin but the cake recipe was written for an 8-inch one, and you need the correct 1.27x factor rather than guessing and ending up with a thin, overbaked layer.
• You are halving a bake and hit '1 egg' and '1 tsp baking powder', where straight division either does not work or ruins the rise, and you want the tool to tell you what to do instead.

Frequently asked questions