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Cups, Grams and Oven Temps: Converting Mid-Recipe

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Converting cups to grams while cooking depends on the ingredient, because a cup measures space and a gram measures weight: a cup of all-purpose flour is about 120 grams, a cup of granulated sugar about 198 grams, and a cup of water about 237 grams. For the oven, multiply Celsius by 1.8 and add 32 to get Fahrenheit, then round to the nearest 25 °F, which is what most recipes do anyway.

How many grams in a cup? It depends on what’s in it

There is no single cups-to-grams number. A cup of flour weighs less than a cup of sugar because flour is full of air, and it weighs more again if you scoop it straight from the bag and pack it down. King Arthur Baking’s ingredient weight chart, which most American bakers work from, gives these:

  • All-purpose flour: 1 cup = 120 g
  • Granulated sugar: 1 cup = 198 g
  • Brown sugar, packed: 1 cup = 213 g
  • Butter: ½ cup (one US stick, 8 tablespoons) = 113 g
  • Olive oil: ¼ cup = 50 g
  • Unsweetened cocoa: ½ cup = 42 g

Water is the easy one. A millilitre of water weighs a gram, so a US cup, about 237 millilitres, is about 237 grams. Milk and stock are close enough to treat the same way.

If you have a scale, set the bowl on it, zero it, and add the ingredient until you reach the weight. It is faster than any cup and there is less to wash.

Salt is the one to watch

Salt is where a volume conversion goes wrong fastest, because the crystals differ so much in size. On the same King Arthur chart, a tablespoon of Diamond Crystal kosher salt weighs about 8 grams, a tablespoon of Morton kosher salt about 16 grams, and a tablespoon of table salt about 18 grams.

So a recipe written for Diamond Crystal and made with table salt gets more than twice the salt. When the brand isn’t named and you’re using fine salt, start with about half the amount and season at the end. You can always add more.

Cups and spoons aren’t the same everywhere

A cup is not one size. The US cup is about 237 millilitres; the metric cup used in Australia, New Zealand and many Canadian recipes is 250. Most British recipes skip cups and go by weight. Tablespoons differ too: the US and UK tablespoon is 15 millilitres, the Australian one is 20.

NIST, the US standards agency, makes the same point in its culinary measurement tips: customary measures such as teaspoons, cups and pints mean different things in different countries, and the safest conversion is to measure with the tool the recipe assumed, then weigh the result.

In a soup or a stew, these differences disappear. In a cake, or with salt, baking powder or yeast, they don’t, so check where the recipe comes from before you convert.

Ounces: weight or fluid?

An ounce can be either. A dry-weight ounce is about 28 grams; a US fluid ounce is about 30 millilitres. “8 ounces of chocolate” is a weight, about 227 grams. “8 fluid ounces of stock” is a volume, one US cup. If the recipe just says “ounces” and the ingredient is solid, it means weight. Pints differ by country as well: a US pint is 473 millilitres, a UK pint 568.

How to convert oven temperature: Celsius, Fahrenheit, gas mark

The formula is Celsius × 1.8 + 32. Recipes round the result, so these are the pairs you’ll see:

  • 150 °C = 300 °F = gas mark 2
  • 160–170 °C = 325 °F = gas mark 3
  • 180 °C = 350 °F = gas mark 4
  • 190 °C = 375 °F = gas mark 5
  • 200 °C = 400 °F = gas mark 6
  • 220 °C = 425 °F = gas mark 7
  • 230 °C = 450 °F = gas mark 8

Fan ovens run hotter for the same setting. British recipes often give both, such as “180 °C, 160 °C fan”. If a recipe gives only the conventional figure and you’re using the fan, set it about 20 °C (25 °F) lower and start checking a little early.

Converting with the pan already hot

Mid-recipe is the worst time to convert a whole ingredient list. Convert only the next ingredient, then the one after. Round sensibly: 113 grams of butter is 115 if your scale counts in fives, and nobody will notice.

Be exact where it counts, which means baking, salt and leaveners, and relaxed with vegetables, herbs and liquids for a braise. When you do work out a conversion, write it on the recipe in pencil, so the second time costs nothing. If you’re converting because you’ve also changed the number of servings, the guide to scaling a recipe covers what doesn’t multiply cleanly. If the unit isn’t the problem but the word is, recipe terms explained covers the common ones.

Checking the step with Kre

Cook with Kre talks you through a recipe one step at a time, with the amounts beside the step. You bring the recipe by link, or paste it in. Ask about the current step and Kre answers from the recipe; when the recipe doesn’t say, it tells you so. It isn’t a conversion chart, so keep a scale or this page handy for that. If you choose a different number of servings before you start, the amounts are scaled for that number. See how Kre cooks with you.

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