Cups to grams depends on what is being measured, because a cup is a volume and a gram is a mass. One cup of all-purpose flour weighs about 120 g, one cup of granulated sugar about 198 g, and one cup of packed brown sugar about 213 g, according to King Arthur Baking's weight chart. Multiply the number of cups by the grams per cup for the ingredient.
Why does cups to grams change by ingredient?
The link between volume and mass is density: mass = density × volume. A US cup is a fixed volume of about 236.6 mL (NIST: 0.2365882 L), and flour, sugar and oats pack differently, so a cup of each weighs a different amount. That is why no single cups-to-grams factor exists, and why converters that give one number are only valid for water-like liquids, where 1 mL weighs about 1 g.
Cups to grams chart for common baking ingredients
| Ingredient | 1 cup | 3/4 cup | 1/2 cup | 1/3 cup | 1/4 cup |
|---|---|---|---|---|---|
| All-purpose flour | 120 g | 90 g | 60 g | 40 g | 30 g |
| Bread flour | 120 g | 90 g | 60 g | 40 g | 30 g |
| Granulated sugar | 198 g | 148.5 g | 99 g | 66 g | 49.5 g |
| Brown sugar, packed | 213 g | 159.8 g | 106.5 g | 71 g | 53.3 g |
| Confectioners' sugar, unsifted | 113 g | 84.8 g | 56.5 g | 37.7 g | 28.3 g |
| Rolled oats (old-fashioned) | 89 g | 66.8 g | 44.5 g | 29.7 g | 22.3 g |
Source for the 1-cup values: King Arthur Baking's Ingredient Weight Chart; the other columns are the 1-cup value multiplied by the fraction. The same chart lists 8 tablespoons (1/2 cup) of butter as 113 g, so 1 cup of butter is 226 g, and 1/2 cup of unsweetened cocoa as 42 g, or 84 g per cup.
Each ingredient has its own value. Another brand or source may list slightly different figures for the same ingredient.
How do you convert cups to grams?
- Find the grams per cup for the ingredient (chart above or the package).
- Multiply by the number of cups.
- Reverse by dividing: grams ÷ grams per cup = cups.
Formula: grams = cups × grams per cup
For 1/3 cup, use the fraction as a decimal (0.333) or divide the 1-cup figure by 3.
Worked examples
Example 1: flour for a loaf
A recipe asks for 2 1/2 cups of all-purpose flour: 2.5 × 120 = 300 g.
Example 2: sugar
1 1/2 cups of granulated sugar: 1.5 × 198 = 297 g.
Example 3: grams to cups
A European recipe calls for 250 g of granulated sugar: 250 ÷ 198 = 1.26 cups, about 1 1/4 cups. A 200 g amount of flour is 200 ÷ 120 = 1.67 cups, about 1 2/3 cups.
Example 4: butter
A stick of butter is 8 tablespoons, or 1/2 cup, and weighs 113 g. Two sticks: 226 g, or 1 cup.
Example 5: water-like liquid
1 cup of water or milk is 236.6 mL. With density near 1 g/mL, that is about 237 g. King Arthur's chart rounds water and milk to 227 g (8 oz) per cup, so for baking by weight follow the recipe's own figure. For volume conversions use cups to ml or ml to cups.
Which is more accurate: cups or grams?
Weighing is. How firmly a cup is packed changes its weight, and a scale removes that variable, which is why many recipes now list grams. When only a cups recipe is available, use the chart above and a scale; use grams to ounces or ounces to grams when the scale is in the other unit.
Cup ounces are a separate topic: a cup holds 8 fluid ounces by volume, but a cup of flour weighs about 4 1/4 weight ounces. The guide to ounces in a cup explains the two. For tablespoons, see tablespoons to cups.
Common mistakes
- Using one factor for everything. 240 g per cup works for water, not for flour (120 g) or sugar (198 g).
- Mixing up volume and weight ounces. 8 fl oz of flour is not 8 oz of flour.
- Mixing ingredient types. Use the figure for the exact ingredient named; bread and all-purpose flour match on King Arthur's chart.
- Ignoring packing. The brown sugar value of 213 g applies to packed sugar.