Powdered Sugar:
Grams to Cups
By Stefan Ulrich · Last updated
Powdered sugar (also called confectioners' sugar or icing sugar) weighs 120 grams per cup — the same as all-purpose flour, but for entirely different reasons. Powdered sugar is ultra-fine ground white sugar, and the cornstarch added to prevent clumping makes it behave more like a light flour than a sugar.
How much Powdered Sugar weighs at each cup measure.
Convert Powdered Sugar
1 cup = 120 grams
= — grams
= — cups
Quick reference
Measurement Table
| Cups | Grams | Ounces |
|---|---|---|
| 1 tsp | 3 g | 0.11 oz |
| 1 tbsp | 8 g | 0.28 oz |
| ⅛ cup | 15 g | 0.53 oz |
| ¼ cup | 30 g | 1.06 oz |
| ⅓ cup | 40 g | 1.41 oz |
| ½ cup | 60 g | 2.12 oz |
| ⅔ cup | 80 g | 2.82 oz |
| ¾ cup | 90 g | 3.17 oz |
| 1 cup | 120 g | 4.23 oz |
| 1¼ cups | 150 g | 5.29 oz |
| 1½ cups | 180 g | 6.35 oz |
| 2 cups | 240 g | 8.47 oz |
| 3 cups | 360 g | 12.70 oz |
About Powdered Sugar
The 120 g/cup figure assumes unsifted powdered sugar spooned into the cup. Sifted powdered sugar weighs noticeably less — approximately 100–105 g/cup — because sifting breaks up clumps and introduces air. When a recipe specifies '2 cups sifted powdered sugar,' the sifting happens before measuring. '2 cups powdered sugar, sifted' means measure first, then sift.
Powdered sugar is used wherever a smooth, lump-free texture is essential: buttercream frosting, royal icing, glaze, and certain cookie doughs. Its fine texture dissolves instantly without the gritty mouthfeel of granulated sugar.
Confectioners' sugar, 10X sugar, and icing sugar are all the same product. '10X' refers to the fineness of the grind. In the UK, icing sugar contains a slightly higher cornstarch ratio and behaves identically for most purposes.
For large batches of frosting, measuring powdered sugar by weight is far less messy than filling cup after cup.
Tips for measuring Powdered Sugar
- Sifted vs. unsifted: sifted = ~105 g/cup; unsifted = ~120 g/cup.
- Always sift when making frosting or royal icing for a smooth result.
- 1 lb powdered sugar = about 3¾ cups (454 g ÷ 120 g = 3.78 cups).
- Store sealed — it absorbs humidity and clumps within hours of opening.
Common mistakes
- Confusing with granulated sugar (200 g/cup) — they are not interchangeable by volume
- Not sifting for frosting — lumpy buttercream is almost always a sifting issue
Frequently Asked Questions
- How many grams in a cup of Powdered Sugar?
- 1 cup of Powdered Sugar weighs 120 grams — the standard used in most American recipes. Use the converter above for any other amount.
- How many grams is 1 tablespoon of Powdered Sugar?
- 1 tablespoon of Powdered Sugar weighs about 8 grams. The full table above lists every common cup fraction.
- What's the most common mistake when measuring Powdered Sugar?
- Confusing with granulated sugar (200 g/cup) — they are not interchangeable by volume. Weighing on a kitchen scale avoids it entirely.
- Do I pack Powdered Sugar into the cup?
- Only pack brown sugars; granulated and powdered powdered Sugar are spooned in loosely and levelled. Packing the wrong type adds significant weight.