Convert Caster Sugar from Ounces to Cup

How many cups is 1 ounce of caster sugar?

1 ounce of caster sugar (castor sugar) is 0.13 cups. 2 ounces of caster sugar is 0.25 cups. 4 ounces of caster sugar is 0.5 cups. 6 ounces of caster sugar is 0.76 cups. Use the converter below for any amount.

  • These figures use the metric cup (250 ml). A US cup is slightly smaller at 240 ml, so it holds a little less. Use the US cup converter →
  • Cup sizes are not standard worldwide, so the same cup of an ingredient can weigh more or less depending on the country. What is a cup measurement →

Caster sugar, also known as superfine or castor sugar, is a key ingredient in many baking recipes due to its fine texture and quick-dissolving properties. Commonly used in cakes, meringues, and desserts, it sits between granulated sugar and powdered sugar in terms of texture. One metric cup (250 ml) of caster sugar weighs around 225 grams or 7.94 ounces.

Since baking is a precise science, even small differences in sugar quantity can affect the final outcome, from texture and sweetness to structure. This page helps you convert caster sugar between grams, cups, tablespoons, and more so that you can follow any recipe confidently, no matter what measurement system it uses.

Also known as

  • castor sugar
  • Superfine Sugar
  • Baker's Sugar
  • Bar Sugar

Standard granulated sugar has larger crystals than caster sugar, so it dissolves more slowly in batters and meringues. They are close in weight (200 g vs 225 g per cup) and swap 1:1 by volume in most recipes, though caster gives a smoother result. See our Sugar converter.

Raw sugar has large, coarse crystals that dissolve slowly, the opposite of fine caster sugar. It packs lighter (200 g vs 225 g per cup), so it is not a 1:1 swap by volume; weigh when substituting. See our Raw Sugar converter.

Out of caster sugar? See caster sugar substitutes →

No scale? The tool below gives a good estimate, but for exact bakes a digital kitchen scale removes the guesswork.

Caster Sugar Measurement Converter

Enter a value and pick your units.

Result

0 Cup

Common Caster Sugar Conversions

Here are the most common caster sugar conversions from ounces to cups.

OuncesCups
1 oz0.13 cups
2 oz0.25 cups
3 oz0.38 cups
4 oz0.5 cups
5 oz0.63 cups
6 oz0.76 cups
8 oz1.01 cups
10 oz1.26 cups
12 oz1.51 cups

Caster Sugar Conversion Chart

The conversion chart below gives a quick reference for converting caster sugar from Ounces to Cup and other measurements.

ouncescupgramscup(US)tbsptsp
2.5 oz0.31 cup70.84 g0.33 cup (US)5.25 tbsp15.74 tsp
5 oz0.63 cup141.69 g0.66 cup (US)10.5 tbsp31.49 tsp
7.5 oz0.94 cup212.53 g0.98 cup (US)15.74 tbsp47.23 tsp
10 oz1.26 cup283.38 g1.31 cup (US)20.99 tbsp62.97 tsp

Frequently Asked Questions

How many cups is 1 ounce of caster sugar?
1 ounce of caster sugar is 0.13 cups. The conversion is fixed, so 2 ounces is 0.25 cups and 4 ounces is 0.5 cups. These whole-ounce amounts are the ones recipes call for most with bulk ingredients, and the figure scales in a straight line as you multiply or divide. Use the converter above for any other amount, or the conversion chart on this page for the common ones. Open the caster sugar converter
How many cups is 2 ounces of caster sugar?
2 ounces of caster sugar is 0.25 cups. The conversion is fixed, so 1 ounce is 0.13 cups and 4 ounces is 0.5 cups. These whole-ounce amounts are the ones recipes call for most with bulk ingredients, and the figure scales in a straight line as you multiply or divide. Use the converter above for any other amount, or the conversion chart on this page for the common ones.
What is 4 oz caster sugar in cups?
4 ounces of caster sugar is 0.5 cups. The conversion is fixed, so 1 ounce is 0.13 cups and 2 ounces is 0.25 cups. These whole-ounce amounts are the ones recipes call for most with bulk ingredients, and the figure scales in a straight line as you multiply or divide. Use the converter above for any other amount, or the conversion chart on this page for the common ones.
What is 6 oz caster sugar in cups?
6 ounces of caster sugar is 0.76 cups. The conversion is fixed, so 1 ounce is 0.13 cups and 2 ounces is 0.25 cups. These whole-ounce amounts are the ones recipes call for most with bulk ingredients, and the figure scales in a straight line as you multiply or divide. Use the converter above for any other amount, or the conversion chart on this page for the common ones.
How many cups is 1 ounce of castor sugar?
Castor sugar is another name for caster sugar, so 1 ounce of castor sugar is 0.13 cups, exactly the same as caster sugar. The figure does not change with the name: 2 ounces is 0.25 cups and 0.5 ounces is 0.06 cups. Use the converter above for any quantity, or read the conversion chart on this page for the most common amounts.
Are caster sugar and castor sugar the same thing?
Yes. Castor sugar is another name for caster sugar, so they are the same ingredient and convert identically. 1 ounce of caster sugar is 0.13 cups under either name, and 2 ounces is 0.25 cups. Recipes use the two names interchangeably, so you can follow either one without changing quantities or weighing any differently.

Other Ingredients

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