This converter changes sugar between grams and US cups for granulated (white), caster (superfine), brown and icing (powdered) sugar. Because each variety packs to a different density, it lets you choose the type for an accurate baking measure, in either direction.
How it works
Each sugar type has a fixed weight per US cup baked into the tool, so conversion is a single multiply or divide:
- Grams → cups: cups = grams ÷ (grams per cup)
- Cups → grams: grams = cups × (grams per cup)
The per-cup weights used are:
| Sugar type | Grams per US cup |
|---|---|
| Granulated / white | 200 g |
| Caster / superfine | 225 g |
| Brown (packed) | 220 g |
| Icing / powdered | 125 g |
Why choosing the sugar type matters so much
The same 150 g of sugar converts to very different cup volumes depending on the variety:
| Sugar | 150 g in cups |
|---|---|
| Granulated | 0.75 cups |
| Caster | 0.67 cups |
| Brown (packed) | 0.68 cups |
| Icing / powdered | 1.20 cups |
Using icing sugar volumes for a granulated sugar recipe — or vice versa — can throw a baked good off by 30 to 60 percent of the intended sweetness and moisture. In a cake batter, the extra liquid and sweetness from icing sugar at the “same cup measure” can collapse the structure. Always match the type to your recipe exactly.
How the varieties differ
Granulated sugar is the workhorse of most baking recipes. Its medium crystals pack loosely into a cup, giving a consistent weight of around 200 g per US cup.
Caster (superfine) sugar has finer crystals that pack more densely, so a cup holds more mass — roughly 225 g. It dissolves faster in cold liquids and creams more smoothly into butter, which is why many British and Australian biscuit and meringue recipes specify it. Converting a US recipe that calls for granulated to grams and then using caster is actually the more precise approach: weigh the grams, skip the cup step entirely.
Brown sugar — whether light or dark — is measured packed firmly into the cup because its molasses content makes it clump. That packing brings it to around 220 g per cup. If a recipe says loosely packed, the weight will be closer to granulated sugar; use your judgement and a scale where precision matters.
Icing (powdered / confectioners’) sugar is the lightest variety, aerated and sifted to a very fine powder. A cup holds only about 125 g. Many bakers sift icing sugar before measuring by weight to avoid lumps in glazes and frostings.
Baking conversion tip
When adapting recipes between US cup-based and metric weight-based formats, convert to grams first and measure by weight. Scales are far more reliable than cups for sugar, because the degree of packing varies by how you scoop. A loosely spooned cup and a tightly packed cup of the same sugar can differ by 20% or more.