How many grams is half a cup of caster sugar?
Half a cup of caster sugar (superfine sugar) weighs
95g
That's 3.4oz. In a 250ml metric cup it's 100g.
This uses the US cup, the size American recipes mean. Half a cup is 118ml by volume.
Caster sugar is finer than granulated, so a cup holds a little less: 190g against 200g.
Other amounts of caster sugar
Where these numbers come from
King Arthur Baking, Ingredient weight chart, checked 2026-10-25. USDA doesn't measure this ingredient, so we use this source instead. It lists:
- Baker's Special Sugar (superfine sugar, castor sugar): 1 cup = 190g
Fractions of a cup are the cup weight scaled down. The tablespoon is the cup weight divided by 16. The teaspoon is a third of the tablespoon. Metric-cup figures assume a 250ml cup, and Australian tablespoons hold 20ml. Weights under 10g are rounded to 0.1g, everything else to the nearest gram. Full source list.