One-Third Cup of Caster Sugar in Grams
1/3 cup of caster sugar weighs 70g (2.47 oz, 80ml) according to USDA FoodData Central (1 cup caster sugar = 210g, spooned and leveled method). 1/3 cup = 0.3333 of a full cup (240ml). See the full conversion table below for all amounts from 1 tablespoon to 3 cups.
Caster Sugar Cup-to-Gram Conversion Table
Full range from 1 tablespoon to 3 cups. The highlighted row shows 1/3 cup.
| Amount | Grams |
|---|---|
| 1 tbsp | 13.13g |
| 2 tbsp | 26.25g |
| 1/8 cup | 26.25g |
| 1/4 cup | 52.5g |
| 1/3 cupthis page | 70g |
| 1/2 cup | 105g |
| 2/3 cup | 140g |
| 3/4 cup | 157.5g |
| 1 cup | 210g |
| 1 1/4 cups | 262.5g |
| 1 1/2 cups | 315g |
| 1 3/4 cups | 367.5g |
| 2 cups | 420g |
| 2 1/2 cups | 525g |
| 3 cups | 630g |
Source: USDA FoodData Central (FDC ID: 19335). 1 US cup = 240ml. Values use spooned-and-leveled method.
1/3 Cup of Different Ingredients — Weight Comparison
1/3 cup of different ingredients varies widely in weight because each has a different density. This matters when substituting ingredients in recipes.
| Ingredient | 1/3 Cup (g) |
|---|---|
| Powdered Sugar | 40g |
| Granulated Sugar | 66.67g |
| Caster Sugarcurrent | 70g |
| Brown Sugar (packed) | 73.33g |
All values use USDA FoodData Central spooned-and-leveled method. Click any ingredient to see its full conversion table.
Measuring Caster Sugar Accurately
Why weight matters: 1/3 cup of caster sugar can weigh anywhere from 60g to 84g depending on how you measure it. The USDA standard is 70g (spooned and leveled). Scooping directly from the container can add 10–20% extra weight, which affects recipe results — especially in baking.
About caster sugar density: Caster sugar (superfine sugar) has finer crystals than regular granulated sugar. 1 cup = 210g. Dissolves faster than regular sugar — ideal for meringues, mousses, cold drinks. Common in UK/Australian recipes.
About 1/3 Cup as a Measurement
1/3 cup = 5 tablespoons + 1 teaspoon = 80ml. This unusual fraction appears in recipes that scale for 2 servings from a 3-serving base. It cannot be made from combining standard 1/4 and 1/8 cup measures without error.
One-third cup is common in yogurt parfait recipes, small-batch granola bars, and single-layer cake recipes scaled for 2 servings. It is exactly 80ml in metric volume.
Frequently Asked Questions
How many grams is 1/3 cup of caster sugar?
1/3 cup of caster sugar weighs 70 grams (2.47 oz, 80ml). Based on USDA FoodData Central: 1 cup caster sugar = 210g, so 1/3 cup = 210 × 0.333 = 70g.
Is 1/3 cup of caster sugar the same weight every time?
The weight can vary slightly depending on measuring technique. Spooned and leveled gives 70g. Scooped (packed) can be 10–20% heavier. Sifted gives a lighter weight. The USDA standard (spooned and leveled) of 70g is the most reliable baseline for recipes.
How do I accurately measure 1/3 cup of caster sugar?
For accuracy, use a kitchen scale and weigh 70g of caster sugar. If using measuring cups, spoon the caster sugar lightly into a 1/3 Cup measuring cup and level off the top with a straight edge. Avoid scooping directly from the container, which compacts the ingredient and adds extra weight.
How does 1/3 cup of caster sugar compare to other ingredients?
1/3 cup of different ingredients varies significantly: Powdered Sugar = 40g, Granulated Sugar = 66.67g, Caster Sugar = 70g. This is because each ingredient has a different density.