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How to halve or double a recipe (and what not to multiply)
Quick answer
Divide the number of servings you want by the number the recipe makes to get a scaling factor (6 servings from a 4-serving recipe is 1.5). Multiply the main ingredients by that factor. Then adjust by eye: add salt, spices and chilli a little at a time rather than multiplying them fully, reduce extra liquid slightly when doubling, use a bigger or second pan, and check doneness rather than trusting the original cooking time.
Recipes are written for four people. You're cooking for two, or six, or making a double batch to freeze. The maths looks simple, and mostly it is. But a few things don't scale in a straight line, and they're the ones that turn a good recipe into an over-salted, under-cooked one.
Step 1: work out the scaling factor
Divide the number of servings you want by the number the recipe makes:
| Recipe serves | You want | Factor |
|---|---|---|
| 4 | 2 | 0.5 (halve) |
| 4 | 6 | 1.5 |
| 4 | 8 | 2 (double) |
| 2 | 5 | 2.5 |
| 6 | 4 | 0.67 (two thirds) |
If the recipe doesn't say how many it serves, estimate from the main ingredient: roughly 125–150g of meat or fish, or 75–100g of dried pasta or rice, per adult portion.
Step 2: multiply the main ingredients
Multiply these by the factor without overthinking it:
- Meat, fish, tofu and beans
- Vegetables
- Pasta, rice, noodles and grains
- Tins of tomatoes, coconut milk and stock
- Cheese, cream and butter in a sauce
Round to sensible shop sizes. A factor of 1.5 on a 400g tin of tomatoes is 600g: one and a half tins. Use two and cook the sauce down a little longer, or freeze the spare half tin.
Step 3: adjust what doesn't scale neatly
Salt, spices and chilli
When doubling, start with about one and a half times the seasoning, then taste and add. Strong flavours compound, and you can always add more but you can't take it out. When halving, halving exactly is usually fine.
Liquid
A bigger pot loses proportionally less liquid to evaporation, so a doubled stew or curry can end up thinner. Hold back a little of the extra stock or water and add it if needed.
Eggs
Halving a one-egg recipe? Beat the egg and use half (a medium egg is about 50g out of its shell). In forgiving recipes like meatballs, fritters or a frittata, you can round up to a whole egg.
Pan size
This is the one people miss. Double the mince in the same frying pan and it steams instead of browning. Double a traybake on one tray and it stews. Use a bigger pan, a second tray, or brown in batches.
Cooking time
Cooking time depends on how thick the food is and how crowded the pan is, not on how much food there is in total. Two chicken breasts take the same time as one, as long as they're not piled up. A bigger stew takes longer to come to the boil, and a larger joint takes longer to cook through. Check doneness rather than trusting the clock: the Food Standards Agency's advice on cooking food properly covers checking that food is steaming hot all the way through, and for poultry, cutting into the thickest part to check there's no pink meat and the juices run clear.
Baking is stricter
Cakes, bread and pastry depend on ratios. Weigh everything, keep baking powder and yeast in proportion, and choose a tin that gives the mixture the same depth as the original. A different tin means a different baking time, so start checking early. If in doubt, make two batches of the original instead of one big one.
Converting old or American measurements
Scaling is easier in grams and millilitres than in cups, ounces or "a knob of butter". If you're working from an old family recipe or an American one, convert it first. Our guide to digitising cookbook and handwritten recipes has a conversion table for ounces, pints, cups and gas marks.
Don't forget the shopping list
Scaling the recipe is pointless if the shopping list still says 500g of mince. Scale before you shop, and if several recipes that week share ingredients, combine them. Our guide to making a shopping list from a meal plan shows how.
Scaling in DinnerSorted
I make DinnerSorted, so I'll be brief. You set how many people you cook for, and when a recipe states how many it serves, the week's grocery list scales its quantities to match and combines them with your other dinners. If a recipe doesn't say how many it serves, DinnerSorted doesn't guess: it leaves the quantities as written, and you can add the servings when you edit the recipe. The seasoning and pan size are still up to you.
Meal planning, the grocery list and Cook Mode are free on iPhone. Recipes can be typed in or imported from TikTok, Instagram, YouTube, websites and photos, with three free imports a month and unlimited imports on DinnerSorted Pro.
Questions people also ask
How do I work out how much to scale a recipe?
Divide the servings you want by the servings the recipe makes. A recipe for 4 that you want for 2 has a factor of 0.5; for 6 it's 1.5; for 8 it's 2. Multiply each ingredient by that number.
Do you double the cooking time when you double a recipe?
No. Cooking time depends on the thickness and size of the food and the pan, not the total amount. A doubled stew may take a little longer to come to the boil, and a bigger joint takes longer to cook through, so check doneness rather than doubling the time.
Should I double the spices when I double a recipe?
Start with about one and a half times the spices, salt and chilli, then taste and add more. Strong flavours can become overpowering when fully doubled.
How do I halve a recipe that uses one egg?
Beat the egg and use half, roughly 25g out of a medium egg's 50g, or keep the whole egg in forgiving recipes like meatballs or fritters. In baking, weigh it.
Can baking recipes be scaled?
Yes, but more carefully. Weigh everything rather than using cups or spoons, keep raising agents in proportion, and match the tin size to the new amount of mixture, which will change the baking time.
Sources
Outside facts in this guide link to their source. The advice and examples are our own.