explainer
Grams to Cups: Why a Cup of Flour Isn't a Cup of Sugar
By the LazyTools team · Published 2026-07-11 · Updated 2026-07-11 · 3 min read
“How many grams in a cup?” has no single answer — and that’s the whole point. A cup measures volume (how much space something fills), but grams measure weight. How much a cup weighs depends entirely on the ingredient’s density: one US cup holds about 120 g of flour, 198 g of sugar, 226 g of butter, and 336 g of honey. Any converter that gives you one fixed “grams per cup” number is wrong for almost everything.
Volume vs weight — the core of it
When a recipe says “1 cup of flour,” it’s telling you to fill a cup-shaped container. But flour is light and full of air, while sugar is dense and packs tightly, and honey is a heavy liquid. Fill the same cup with each and you get very different weights. That’s why there’s no universal conversion — the number of grams in a cup is a property of the ingredient, not of the cup.
The weights that matter most
Using King Arthur Baking’s Ingredient Weight Chart (the US baking standard), per US cup (236.6 mL):
| Ingredient | Grams per cup |
|---|---|
| All-purpose / bread / cake flour | 120 g |
| Whole wheat flour | 113 g |
| Granulated (white) sugar | 198 g |
| Brown sugar (packed) | 213 g |
| Confectioners’ (powdered) sugar | 113 g |
| Butter | 226 g |
| Water / milk | 227 g |
| Honey | 336 g |
| Cocoa powder | 84 g |
Notice how flour and powdered sugar land near 113–120 g (light, airy), while granulated sugar, butter and water cluster around 200–227 g, and honey — a dense liquid — tops 330 g. Same cup, wildly different weights.
Why weighing beats scooping
Flour is the troublemaker. Scoop it straight from the bag and you compress it; a “cup” measured that way can weigh 140 g or more instead of 120 g — over 15% extra, enough to make a cake dry or a cookie tough. Spoon it into the cup and level it and you get closer to 120 g, but it’s still inconsistent from person to person.
A kitchen scale removes all of that: 120 g of flour is 120 g every time, regardless of how packed it is. It’s faster, more accurate, and means one fewer measuring cup to wash. This is why nearly every professional recipe — and a growing number of home baking books — lists ingredients by weight.
The cup that isn’t a cup
One more trap: not all cups are equal. The US customary cup is 236.6 mL, but the metric cup used in Australia, New Zealand and much of Europe is 250 mL — about 6% larger. Older UK recipes sometimes used a different cup again. Gram-per-cup charts (including the one above) almost always mean the US cup, so if you’re measuring with a 250 mL metric cup, you’ll scoop slightly more. For the amounts in baking, that 6% can be the difference between success and a flop — another reason to switch to grams.
The grams to cups converter is ingredient-aware: pick flour, sugar, honey or any of two dozen common ingredients and it converts using the correct weight for that item, in either direction, right in your browser — nothing uploaded.
Sources: ingredient weights are from King Arthur Baking’s Ingredient Weight Chart; cup volume definitions follow NIST. Weights are per US customary cup and are typical values — actual weights vary a little with humidity, brand and how the ingredient is packed.
Frequently asked questions
How many grams are in one cup?
It depends entirely on the ingredient, because a cup measures volume while grams measure weight. One US cup is about 120 g of all-purpose flour, 198 g of granulated sugar, 226 g of butter, 227 g of water or milk, and 336 g of honey. There is no single grams-per-cup number.
How many grams of flour are in a cup?
About 120 g of all-purpose, bread or cake flour per US cup (whole wheat is about 113 g), using King Arthur Baking's standard. Because flour compresses, scooping straight from the bag can pack in 20% or more than 120 g — which is exactly why weighing is more reliable.
Why does a cup of sugar weigh more than a cup of flour?
Density. Sugar granules are heavier and pack together more tightly than the light, air-filled particles of flour. So the same volume — one cup — holds 198 g of sugar but only 120 g of flour.
Is a US cup the same as a metric cup?
No. A US customary cup is 236.6 mL; the metric cup used in Australia, New Zealand and much of Europe is 250 mL — about 6% larger. Gram weights per cup are usually quoted for the US cup, so a metric-cup measure holds slightly more.
Should I bake by weight or by cups?
By weight, whenever you can. A digital scale removes the biggest source of error in baking — how tightly you pack a cup — and it's faster and means fewer dishes. Most professional recipes and serious baking books give weights for this reason.
How do I convert a recipe from cups to grams?
Multiply the number of cups by the ingredient's grams-per-cup weight: 2 cups of flour × 120 g = 240 g. Because that weight differs for every ingredient, use an ingredient-aware converter rather than one fixed number.
Where do these gram weights come from?
The weights used here are from King Arthur Baking's Ingredient Weight Chart, the widely-cited US baking reference, measured with their standard 'fluff, sprinkle, level' method for dry ingredients.