How to Scale a Recipe Up or Down (Without the Maths)

To scale a recipe, divide the servings you want by the servings the recipe makes, and multiply every amount by that number. A recipe for 4 that you want for 6 has a factor of 6 ÷ 4 = 1.5. Then round each amount to something you can actually measure, and adjust the pan and the cooking time, which do not scale the same way.

The multiplication is the easy bit. The rounding, the eggs and the oven are where scaled recipes go wrong, so most of this guide is about those, with real examples from recipes in Matlaro's catalogue.

Step one: find the factor

Write the factor at the top of the recipe before you touch an ingredient. It saves doing the division again for every line.

Step two: round to what you can measure

A scaled amount is only useful if you can measure it. Here is how to round each kind of ingredient, using the same rules Matlaro uses when you change the servings.

Worked example: Spicy Arrabiata Penne, 4 to 6

Factor 1.5. This is what the amounts become:

Going the other way, from 4 down to 1, the chilli flakes become ⅛ tsp and the tomatoes would be a quarter tin. That rounds up to half a tin, which is the honest answer: open the tin, use half, and freeze the rest.

Worked example: Kidney Bean Curry, 2 to 3

Factor 1.5. The 2 teaspoons of garam masala become 3 teaspoons, which is exactly 1 tablespoon, so you use one spoon instead of three. The onion becomes 1½ onions, and the 400 g tins of tomatoes and beans become 600 g each.

Eggs: the ingredient that breaks the maths

Eggs cannot be split cleanly, and in baking they set the structure. Two options:

1. Round to a whole egg when the recipe is forgiving: omelettes, fried rice, most savoury dishes.
2. Beat and weigh when the recipe is not: cakes, custards, batters. Beat the eggs, weigh the bowl, and use the share you need by weight.

Yorkshire Puddings make 8 with 140 g flour, 4 eggs and 200 ml milk. For 6 that is 110 g, exactly 3 eggs and 150 ml. For 3 it is 55 g, 1.5 eggs rounded to 2, and 75 ml. The batter for 3 will be a touch eggier, which in this case is no bad thing. In a cake, you would beat and weigh instead.

Pans: scale by area, not diameter

When you double a cake, you do not need a pan twice as wide. You need twice the area.

A 20 cm cake doubled wants about 628 cm², so a 28 cm pan is close. Halving a 26 cm recipe lands near an 18 or 20 cm pan. A square 20 × 20 cm tin is 400 cm², a little more than a 23 cm round.

Cooking times do not scale

The same goes for:

• Frying and searing. Twice the meat does not fit in the same pan. Cook it in batches, or it steams instead of browning.
• Salt and chilli. Scale them, then taste before you add the last of it. Heat builds up in a large pot.
• Rising and resting. Dough rises on time and temperature. A bigger batch does not rise faster.

Let the app do the maths

In Matlaro, every recipe has a servings control. Change it and every amount follows, with the rounding above applied for you: 680 g, not 675; 5 cloves, not 4.5; 1 tablespoon, not 3 teaspoons.

It works the same on recipes you save yourself, from a link, a photographed page or a caption.

Cooking for a crowd from a family recipe? Digitizing grandma's cookbook gets the old cards into a form you can scale. Cooking smaller for two? Five cheap dinners for two uses exactly this to turn recipes for 4 into dinners for 2.