How Many Grams in a Cup of Caster Sugar?
One cup of caster sugar weighs 225 grams — noticeably more than granulated sugar's 198 grams, because its finer crystals pack together with less air between them. That is why swapping the two sugars by the cup throws a recipe off. Below are the conversion tables for caster sugar, a converter for any amount, and how to measure it.
Convert caster sugar instantly
This converter uses the same chef-reviewed database as our Cups to Grams converter for all 128 ingredients. Weights assume a US cup of 236.588 ml; see our methodology and sources.
Cups to grams: caster sugar
| Cups | Grams |
|---|---|
| ¼ cup | 56 g |
| ⅓ cup | 75 g |
| ½ cup | 113 g |
| ⅔ cup | 150 g |
| ¾ cup | 169 g |
| 1 cup | 225 g |
| 1½ cups | 338 g |
| 2 cups | 450 g |
| 3 cups | 675 g |
| Measure | Grams |
|---|---|
| 1 tablespoon | 14.1 g |
| 1 teaspoon | 4.69 g |
| 1 cup in ounces | 7.9 oz |
Grams to cups: caster sugar
| Grams | Cups (decimal) | Cups (fraction) |
|---|---|---|
| 50 g | 0.22 cups | ¼ cups |
| 100 g | 0.44 cups | ½ cups |
| 125 g | 0.56 cups | ½ cups |
| 150 g | 0.67 cups | ⅔ cups |
| 200 g | 0.89 cups | ⅞ cups |
| 250 g | 1.11 cups | 1 ⅛ cups |
| 300 g | 1.33 cups | 1 ⅓ cups |
| 400 g | 1.78 cups | 1 ¾ cups |
| 500 g | 2.22 cups | 2 ¼ cups |
Working with more than one ingredient? The grams in a cup chart puts 40 ingredients in one table, and the Whole Recipe Converter converts a full ingredient list in a single paste.
How to measure caster sugar properly
Swap it by weight, never by volume. Caster and granulated sugar are chemically the same thing, so any recipe converts perfectly — at equal grams. A cup-for-cup swap sneaks in 27 extra grams (225 against 198), which is enough to oversweeten a sponge and change its texture.
Make it in a minute. Blitz ordinary granulated sugar in a food processor for 30 to 60 seconds, letting the dust settle before you open the lid. You are aiming for crystals that feel like fine sand; stop well short of powdered sugar, which is a different ingredient with starch added.
It settles in the cup. Fine crystals pack down under their own weight, so spoon caster sugar in and level it rather than pouring from a height and shaking the cup level — the same loose fill the 225-gram figure assumes.
Frequently asked questions
How many grams are in a cup of caster sugar?
225 grams. Caster sugar (superfine sugar in the US) is ground finer than granulated sugar, so more crystals fit into the cup with less air between them — the reason it outweighs granulated sugar's 198 grams per cup by 27 grams.
Can I use granulated sugar instead of caster sugar?
Yes, at the same weight: 225 grams of granulated sugar replaces a cup of caster sugar exactly. The difference shows in texture, not sweetness — caster dissolves faster, which is why meringues, sponges and cocktails specify it. Do not swap cup for cup.
How many grams are in a tablespoon of caster sugar?
14.1 grams — a little more than a tablespoon of granulated sugar (12.4 grams), again because the finer crystals pack tighter. A teaspoon of caster sugar weighs about 4.7 grams.