Recipe Scaler

Scaling a recipe is straightforward arithmetic: every ingredient multiplies by the same factor. If a dish serves 4 and you need to serve 6, the scaling factor is 6 ÷ 4 = 1.5, and every quantity in the recipe — flour, sugar, salt, eggs, stock — multiplies by 1.5. The calculator does that for you for any single ingredient at a time.

How the calculation works

The formula is new amount = original amount × (desired servings ÷ original servings). The same factor applies to every ingredient, so once you know the scaling factor (shown alongside the result), you can apply it to the rest of the recipe in your head.

A worked example

A bolognese recipe serves 4 and uses 500 g mince, 1 onion, 400 g chopped tomatoes and 1 tbsp tomato purée. To serve 10, the factor is 10 ÷ 4 = 2.5. New quantities: 1.25 kg mince, 2½ onions, 1 kg tomatoes, 2½ tbsp purée. Round eggs and onions to whole numbers as you go.

Why this matters

Cooking for a dinner party, a family gathering or batch-cooking for the week all require scaling, and "eyeballing" larger amounts is where most home-cooked meals go wrong: too little salt, too much liquid, a sauce that won't reduce in the time the recipe gave. Scaling explicitly — and writing the new quantities on a sticky note before you start — makes large meals just as reliable as the original.

What doesn't scale linearly

• Cooking time: A double batch of stew doesn't take double the simmer time. Larger pans heat slower and lose heat slower, so simmer time grows but not proportionally. Use temperature and texture, not the clock.
• Salt and strong spices: Scale first, then taste. Doubling a chilli recipe with whole dried chillies can leave it too hot — perception of heat isn't quite linear.
• Pan size: A scaled cake batter won't fit in the same tin. Use a bigger tin or split between two, and drop the temperature slightly since deeper batter takes longer to cook through. The Oven Temperature Converter can help if you're also switching between fan and conventional.
• Baking soda / baking powder: Usually scale linearly, but for very large batches some bakers reduce slightly to avoid a metallic taste.

Common mistakes

• Scaling only the "main" ingredients and forgetting salt, oil or stock.
• Keeping the original tin or pan size — too-deep batter doesn't bake evenly.
• Doubling cooking time. Test with a skewer, thermometer or by eye.
• Scaling baked goods by very large factors. Yeasted breads in particular work best at moderate factors (0.5–2×); beyond that, dough behaviour changes.

Beyond the numbers

Baking is essentially chemistry with butter, and chemistry doesn't always scale on a single line. Doubling a sponge increases the volume of batter eightfold relative to the surface area of the tin — that's why a "double" cake baked in a single deep tin comes out raw in the middle and dry at the edges. The fix is geometric, not arithmetic: split the batter across two tins, or step up to a wider one, so the depth stays similar to the original.

Seasoning behaves the same way. Salt scales linearly because we taste it linearly, but heat, garlic and acid don't — a chilli that's pleasantly warm at four portions can be overwhelming at ten if you simply triple the dried chillies. The reliable approach is to scale the recipe on paper, then taste at the end and adjust the strong elements. For weight conversions of any scaled ingredient, the Cups to Grams converter handles the translation in one step.

Other kitchen helpers: Butter Conversion, Oven Temperature, Cups to Grams and Grams to Cups.