Cups to grams: a baking conversion chart that tells you why flour varies

Ask three trusted baking sources how much a cup of flour weighs and you can get three answers. King Arthur Baking says 120 grams. America's Test Kitchen says 142. Pack the cup down hard and it can hold 160. Same flour, same cup, a third more flour in the bowl.

That's why converting cups to grams (or grams to cups) is a little more than looking up one number. Below is a chart for the ingredients you bake with most, the two-line formula that does the rest, and the reason flour causes all the arguments.

Cups to grams chart for common baking ingredients

These figures come from King Arthur Baking's ingredient weight chart, which many bakers use as a reference. They're for US cups. King Arthur lists a few ingredients by the half cup or tablespoon (butter, cocoa, rice, honey), so we've multiplied those up to a full cup. Everything is rounded to the nearest gram.

A few things worth knowing about that table:

• Butter: one US stick is 8 tablespoons, or ½ cup, which is 113 g (America's Test Kitchen's conversion chart agrees).
• Honey is heavy. King Arthur weighs it at 21 g per tablespoon, and there are 16 tablespoons in a cup.
• Milk and water: King Arthur rounds a cup of liquid to 8 ounces, or 227 g. A US cup is about 237 ml by NIST's measurement tables, so a cup of water you weigh yourself may read closer to 237 g. A 10 g difference rarely matters outside bread dough.

How to convert cups to grams, and grams to cups

Once you have the grams-per-cup number, it's one step either way.

Cups to grams. Your cookie recipe calls for 2¼ cups of all-purpose flour:

2.25 × 120 g = 270 g

Grams to cups. A British recipe asks for 250 g of flour and you only have cups:

250 g ÷ 120 g = 2.08 cups

That's 2 cups plus a little extra. A cup holds 16 tablespoons, so 0.08 of a cup is about 1⅓ tablespoons. Round it to 2 cups plus 1 heaping tablespoon and you'll be close.

Butter works the same way. 150 g of butter ÷ 226 g = 0.66 cups, which is about ⅔ cup, or a stick and a quarter with a little left over.

The one mistake to avoid: using a single number for every ingredient. "1 cup = 240 g" is roughly right for water and badly wrong for flour. Two cups of flour converted at 240 g a cup gives you 480 g, double what the recipe wanted.

Why flour weighs 120 g in one recipe and 142 g in another

Flour is fluffy. How much of it lands in a cup depends on how much air you leave in.

There are two common ways to fill a cup:

1. Spoon and level. Stir the flour to loosen it, spoon it into the cup until it's heaped, then sweep the top flat with a knife. King Arthur calls this "fluff, sprinkle, and scrape", and it gives about 120 g. Every King Arthur recipe assumes this method.
2. Dip and sweep. Push the cup into the flour bag, then level it off. America's Test Kitchen uses this method, and it had dozens of volunteers measure a cup and averaged the results to get its standard of 5 ounces, or about 142 g.

Neither is wrong. They're different recipes' house rules. Trouble starts when you bake a spoon-and-level recipe with a scooped cup. ATK found up to a 20 percent difference in a cup of flour depending on the method and the baker, and King Arthur says a densely packed cup can hold up to 160 g. King Arthur's PJ Hamel puts the result plainly: extra flour means dry, tough bread.

So before you convert a recipe's flour, check the source:

• The recipe already lists grams? Use them and ignore the cups.
• It's from King Arthur? Use 120 g per cup.
• It's from America's Test Kitchen or Cook's Illustrated? Use 142 g per cup.
• It's from a blog? Look for a note on how the writer measures flour. If there isn't one, ask in the comments before you bake.

Brown sugar has its own version of this. King Arthur's 213 g is for packed brown sugar, pressed into the cup until it holds its shape. Loosely spooned brown sugar weighs less.

For recipe writers: weigh your own cup

If you publish recipes in cups and want to add grams, the chart is a starting point. The number that belongs on your recipe card is what your cup weighs when you fill it.

Here's why. Say you've always scooped your flour. Your chocolate cake works because it has about 142 g of flour per cup in it. Convert it with King Arthur's 120 g and your gram readers get a wetter, different cake than your cup readers.

So add grams like this:

1. Fill the cup exactly the way you always have. If you scoop, scoop. Changing your method now changes the recipe.
2. Tare the scale, tip the cup into the bowl and write down the weight. Repeat for each cup-measured ingredient.
3. Check how each ingredient is prepared before you measure it. "1 cup walnuts, chopped" means measure, then chop. "1 cup chopped walnuts" means chop, then measure. Virginia Cooperative Extension's recipe-writing guide explains the convention, and the two give different amounts.
4. Bake it once from the grams alone, to be sure the numbers make the recipe you meant.

Then write both measures on the same line, cups first if your readers mostly use cups:

2 cups (284 g) all-purpose flour, scooped and leveled

1 cup (213 g) packed light brown sugar

½ cup (113 g) unsalted butter, softened

Telling readers how you filled the cup is a small kindness. It answers the question before it lands in your comments.

If an ingredient is marked "divided", make sure the gram amounts in the steps add up to the total in the ingredient list. And once the grams are in, scaling gets much easier. Halving 284 g is simple; halving 2⅓ cups isn't. Our guide to scaling a recipe shows the method.

Your next step

If you cook from other people's recipes, keep the chart handy and check how the writer measures flour before you convert. If you write recipes, weigh your own cups this week, then bake once from the grams. Our guide to testing a recipe covers what to write down, and how to write a recipe covers the rest of the ingredient list. When the numbers are settled, put both measures on your printable recipe cards so nobody has to convert at the stove.

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