Recipe scaler — portion calculator

Divide the target number of servings by the original number to get the scaling factor, then multiply every ingredient by that factor. Example: recipe for 4, you want 6 — factor = 6 ÷ 4 = 1.5. Multiply each ingredient by 1.5.

Most ingredients (flour, sugar, meat, vegetables) scale linearly. Exceptions: spices and salt often need less than the calculated amount (taste does not scale linearly), baking powder and yeast — use slightly less when scaling up greatly, baking time — depends on volume, not weight, and does not scale linearly.

Scaling down works the same way: factor = new ÷ original. For 8 servings down to 2: factor = 2 ÷ 8 = 0.25. Multiply every ingredient by 0.25. For small quantities, weigh ingredients rather than using volume spoons — weighing is more accurate.

Changing the tin size requires adjusting by the ratio of surface areas: (new diameter / old diameter)². For 26 cm instead of 20 cm: (26/20)² = 1.69. Multiply all ingredients by 1.69. A dedicated tin-size calculator is the right tool; the portion calculator is for scaling by number of servings.

Convert to convenient equivalents: 1.5 tablespoons = 1 tablespoon + 1.5 teaspoons; 0.75 cup = 3/4 cup = 12 tablespoons; 375 g = 1.5 packs of 250 g. You can also round slightly — small deviations rarely affect the dish.

Cooking time does not scale proportionally. For soups, sauces, pasta — time stays similar or increases slightly (10–20%). For cakes and roasts — time depends on thickness/volume, not weight. Doubling a cake recipe may add 15–30% to baking time. Best practice: check doneness with a skewer or thermometer.

When scaling above ×5: use kitchen scales instead of volume measures, add spices gradually and taste rather than multiplying blindly, use 80–90% of the calculated baking powder/yeast, check internal temperature with a thermometer. Consider cooking several smaller batches instead of one enormous one.

Yes — if you know the calorie count for the original number of servings, the factor tells you how to adjust. Example: recipe for 4 contains 1,200 kcal total (300 kcal/serving). Cooking for 1: factor = 0.25, so you use 0.25 of the recipe and still get 300 kcal. Useful for meal planning and batch cooking.

Convert to metric first, then scale. Useful conversions: 1 cup (US) = 240 ml, 1 oz = 28 g, 1 lb = 454 g, 1 fl oz = 30 ml, 1 tablespoon (US) = 15 ml, 1 teaspoon = 5 ml. Once in grams and millilitres, multiply by the scaling factor.

After calculating the factor, work out the quantities of each ingredient and round up to the nearest pack size (e.g. 375 g flour → buy 500 g). For parties: calculate all recipes, sum up the same ingredients across dishes, then go shopping once. The portion calculator makes this faster — just read off the scaling factor and apply it.