1 cup powdered sugar = 120 grams
Volume is only half the story. Powdered sugar weighs 120 g per US cup (unsifted), so we convert with a tested, ingredient-specific factor instead of a generic table.
Powdered sugar cups to grams
Unsifted · rounded for kitchen use
| Cups | Grams | Ounces |
|---|---|---|
| ¼ cup | 30 g | 1.058 oz |
| ⅓ cup | 40 g | 1.411 oz |
| ½ cup | 60 g | 2.116 oz |
| ⅔ cup | 80 g | 2.822 oz |
| ¾ cup | 90 g | 3.175 oz |
| 1 cup | 120 g | 4.233 oz |
| 1 ½ cups | 180 g | 6.349 oz |
| 2 cups | 240 g | 8.466 oz |
| 3 cups | 360 g | 12.7 oz |
Exact factor details
- Exact factor
- 1 cup = 120 g (unsifted)
- Significant digits
- 3 significant figures for table display
- Data source
- USDA FoodData Central (unsifted)
Why powdered sugar conversions vary
Powdered sugar (confectioners' sugar) is measured unsifted at 120 g per US cup. Sifting aerates it dramatically — a sifted cup can weigh 20-30 g less — so recipes specify which they mean. For frostings and glazes, unsifted weight plus a quick whisk in the bowl gives the most repeatable results.
Our factor for powdered sugar — 120 g per US cup — comes from USDA FoodData Central (unsifted). Weighing beats measuring cups for repeatability: a scale gives the same result every time regardless of how the ingredient settled, and it scales recipes cleanly. Note that a US cup (236.6 ml) and a metric cup (250 ml) are not the same; recipes from outside North America may assume the metric size, which shifts every weight by about five percent.
The table below lists the amounts bakers actually reach for — quarters, thirds, and halves of a cup through three full cups — computed directly from the factor above. The converter handles any other amount instantly and uses the exact same number, so the quick reference and the live result can never drift apart.
Frequently asked questions
How much does 1 cup of powdered sugar weigh?
One US cup of powdered sugar weighs 120 g (unsifted). This comes from USDA FoodData Central (unsifted).
Why do some recipes list a different weight for powdered sugar?
Measuring conventions and brands differ, and packing changes the weight. We state our convention openly; when a recipe names its own gram value, follow that one for best results.
Should I measure powdered sugar by cups or by weight?
Weight, whenever the recipe allows. Measure unsifted, then sift together with other dry ingredients only when the recipe calls for it.