⚖️ Comparison · Updated for 2026
Caster Sugar vs Granulated / Icing Sugar
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
Quick answer: Granulated: large crystals, standard table sugar. Caster: finer crystals, dissolves faster — UK baking default. Icing (US 'powdered'): finest, contains cornstarch, used for frostings/dusting. Substituting incorrectly is the most common cause of grainy or under-risen bakes.
Decision guide — when to use which
Use Caster Sugar when…
UK creamed cake batters, meringues, sponges, anywhere fast-dissolving sugar matters.
Use Granulated / Icing Sugar when…
Granulated: tea/coffee, savoury cooking, crystal-topped pies. Icing: frosting, dusting, royal icing.
📊 Side-by-side comparison
| 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
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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.
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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.
Reviewed for 2026. All conversion factors and historical references verified against official sources (ISO standards, government weights & measures legislation, IEC technical specifications). Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project. We don't sell SEO links or accept paid placements in this content.