Caster Sugar vs Granulated / Icing Sugar
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
UK creamed cake batters, meringues, sponges, anywhere fast-dissolving sugar matters.
Granulated: tea/coffee, savoury cooking, crystal-topped pies. Icing: frosting, dusting, royal icing.
| Aspect | Caster Sugar | Granulated / Icing Sugar |
|---|---|---|
| Crystal size | Fine | Coarse / Powder |
| Best for | UK baking, meringue | Granulated: cooking. Icing: frosting |
| Sweetness | Same as granulated | Same / 95% sugar + 5% starch |
| Substitute in pinch | Pulse granulated in blender briefly | Granulated for caster (works in most cases) |
Frequently asked
Can I use granulated instead of caster sugar?
In most cake recipes, yes — but cream the butter longer to dissolve the larger crystals. In meringues, no — granulated will leave grit. In sponges, expect slightly denser texture.
What is US 'superfine sugar'?
US superfine sugar = UK caster sugar. Same product, different names. The US 'baker's sugar' label also matches UK caster.
Frequently asked questions
Can I use granulated instead of caster sugar?
In most cake recipes, yes — but cream the butter longer to dissolve the larger crystals. In meringues, no — granulated will leave grit. In sponges, expect slightly denser texture.
What is US 'superfine sugar'?
US superfine sugar = UK caster sugar. Same product, different names. The US 'baker's sugar' label also matches UK caster.