One US cup of all-purpose flour weighs about 125 g, a cup of granulated sugar about 200 g and a cup of butter about 227 g. Those three numbers differ because a cup measures volume, not mass: to turn cups into grams you need the volume of the cup and the density of the ingredient. This guide gives both, in a table that matches the SamemaS Cups to Grams tool, notes where King Arthur Baking and the USDA disagree, and explains why "a cup" means four different volumes depending on where the recipe was written.

Bar chart of grams in one US cup for 16 ingredients, from cocoa powder at 85 g and rolled oats at 90 g up to maple syrup at 322 g and honey at 340 g, with King Arthur Baking values shown as dots close to most bars
Chart: grams per US cup in the SamemaS tool (bars) against the King Arthur Baking ingredient weight chart (dots). The biggest gaps are cake flour, rice, vegetable oil and milk.

What is a US cup?

The US customary cup is half a US pint, or 8 US fluid ounces. Because the US fluid ounce is defined through the cubic inch, the cup works out to 236.5882365 mL, usually written 236.6 mL. That is the cup American recipes mean, and it is the one the SamemaS tool uses (236.588 mL, with a 14.787 mL tablespoon and a 4.929 mL teaspoon).

Three other cups cause most conversion mistakes:

An older Canadian cup of 8 imperial fluid ounces (227.3 mL) also turns up in vintage Canadian cookbooks. It is 3.9% smaller than the US cup.

Horizontal bars comparing five cup definitions: old Canadian cup 227.3 mL, US customary cup 236.6 mL, US nutrition-label cup 240 mL, metric cup 250 mL and half an imperial pint 284.1 mL, which is 20.1 percent larger than the US cup
Chart: the five volumes called "a cup", computed from their legal or traditional definitions.
Three plastic measuring cups, yellow, blue and green, with handles marked 1/4 cup 60 ml, 1/2 cup 125 ml and 1 cup 250 ml
Check the handle: these cups are marked ¼ cup = 60 mL, ½ cup = 125 mL and 1 cup = 250 mL, so they are metric cups. Measured with them, a US recipe comes out 5.7% larger than intended. Photo: Vimkay, CC BY-SA 4.0, via Wikimedia Commons (resized).

Cups to grams chart

The 1-cup column is exactly what the SamemaS Cups to Grams tool uses. The fractions were computed from it and rounded to the nearest gram; the tablespoon column is the tool's own per-tablespoon value.

Ingredient (grams)1 cup3/4 cup1/2 cup1/3 cup1/4 cup1 tbsp
All-purpose flour125946342317.8
Bread flour127956442327.9
Cake flour100755033256.25
Whole wheat flour120906040307.5
Almond flour96724832246
Cocoa powder85644328215.3
Granulated sugar200150100675012.5
Brown sugar (packed)220165110735513.8
Powdered sugar120906040307.5
Butter227170114765714.2
Vegetable oil218164109735513.6
Honey3402551701138521.3
Maple syrup3222421611078120.1
Whole milk244183122816115.25
Water236.6177118795914.8
White rice (uncooked)18513993624611.6
Rolled oats90684530235.6
Chocolate chips17012885574310.6

A US stick of butter is 1/2 cup, or 4 oz, which is 113.4 g; packages usually print 113 g. The table's 114 g for 1/2 cup is the tool's 227 g halved and rounded, so treat the two as the same.

Why the published figures disagree

Different references give different gram values for the same cup, and none of them is wrong. They measured differently.

For dry ingredients, method matters more than brand. America's Test Kitchen reports that scooping technique alone can cause "up to a 20 percent difference" in the weight of a cup of flour, because dipping the cup into the bag compacts it. Its own standard is 5 oz (142 g) per cup, measured by dipping and sweeping. That explains why American recipe writers' flour weights range from 120 g to 142 g.

Tip: follow the recipe writer's method

If a recipe was developed with King Arthur's 120 g cup and you scoop at 150 g, you add 25% more flour than intended, enough to turn a soft cookie into a dry one. When a recipe gives grams, use them. When it only gives cups, check whether the author says "spooned and leveled" or "dip and sweep", and pick the matching figure.

Worked examples

1. A US cookie recipe in grams

A typical chocolate chip cookie recipe calls for 2 1/4 cups flour, 3/4 cup granulated sugar, 3/4 cup packed brown sugar, 1 cup butter and 2 cups chocolate chips. Using the table:

  1. Flour: 2.25 × 125 g = 281 g (or 270 g with King Arthur's 120 g cup).
  2. Granulated sugar: 0.75 × 200 g = 150 g.
  3. Brown sugar: 0.75 × 220 g = 165 g.
  4. Butter: 1 × 227 g = 227 g, or two US sticks.
  5. Chocolate chips: 2 × 170 g = 340 g.

The flour line shows why the method matters: 2 1/4 cups scooped at 150 g each would be 338 g, 20% more than the 281 g above.

2. An Australian recipe on a US kitchen scale

An Australian recipe calls for 2 cups of plain flour. Those are 250 mL metric cups.

  1. Total volume: 2 × 250 mL = 500 mL.
  2. In US cups: 500 ÷ 236.59 = 2.11 US cups.
  3. In grams: 2.11 × 125 g = 264 g.
  4. If you wrongly measure 2 US cups instead, you get 2 × 125 g = 250 g, which is 5.4% short.

A 5% difference rarely ruins a cake, but it adds up when every ingredient in a recipe is off by the same amount in the same direction. The SamemaS Cooking Converter handles the volume step (mL to US or UK cups); the Cups to Grams tool then gives the mass.

Water and other liquids

A US cup of water holds about 236 g. Water's density is slightly below 1 g/mL at kitchen temperature (0.998 g/mL at 20 °C), which gives 236.2 g; the tool rounds to 236.6 g by treating water as exactly 1 g/mL. If you see "1 cup of water = 240 g", the writer used the 240 mL nutrition-label cup. For milk, oil and syrups, the density sets the answer: oil is lighter than water (about 218 g per cup in the tool), and honey is much heavier (340 g). For an ingredient the tool does not list, find its density, convert it to g/mL with the density converter if it is given in lb/ft³ or another unit, and multiply by 236.6 to get grams per US cup.

How the SamemaS Cups to Grams tool works

The Cups to Grams tool lists 30 ingredients, from flours and sugars to oils, dairy, nuts and chocolate. Pick one, choose cup, tablespoon or teaspoon, and type an amount: it shows grams, kilograms, ounces and pounds. You can also type into the grams, kilograms, ounces or pounds field to go the other way and see US cups, tablespoons and teaspoons. All values are averages, and the tool itself warns that the real weight varies with brand, humidity and packing method. It works in US measures only, so convert metric or UK cups to US cups first. For whole-recipe conversions from kilograms and pounds, see our guide to kilograms and pounds.

Quick checklist

Frequently asked questions

1How many grams is 1 cup of all-purpose flour?
About 125 g per US cup in the SamemaS tool and the USDA database. King Arthur Baking uses 120 g, measured by spooning and leveling. Scooping straight from the bag packs the flour and can give 140 g or more.
2How many mL is a US cup?
A US customary cup is 8 US fluid ounces, or 236.5882365 mL, usually written 236.6 mL. Nutrition labels use a rounded 240 mL cup under FDA rule 21 CFR 101.9. Australia, New Zealand and Canada use a 250 mL metric cup.
3Is a cup of butter 227 grams?
Yes. A US cup of butter is two sticks of 4 oz each, or 8 oz, which is 226.8 g, rounded to 227 g. One stick (1/2 cup) is 113 g.
4Why do Australian cup recipes come out different?
An Australian cup is 250 mL, 5.7% larger than the 236.6 mL US cup. Two Australian cups of flour are 500 mL, or 2.11 US cups, about 264 g. Measuring 2 US cups instead gives 250 g, 5.4% less.

Sources

  1. Ingredient Weight Chart — King Arthur Baking
  2. Guidelines for Determining Metric Equivalents of Household Measures — U.S. Food and Drug Administration
  3. Cup (unit) — Wikipedia
  4. Flour Volume to Weight — America's Test Kitchen
  5. Wheat flour, white, all-purpose (USDA portion weights) — ReciPal, citing USDA
  6. Rice, white, long-grain, raw (USDA NDB 20044 portion weights) — ReciPal, citing USDA