Digital Kitchen Scale
Essential for cup-to-gram accuracy and repeatable bakes.
Shop scales ↗Also known as superfine sugar, castor sugar, baker's sugar.
Finely milled granulated sugar — the default baking sugar in the UK and Australia. Sold as superfine or Baker's Special sugar in the US.
Also Called
superfine sugarcastor sugarbaker's sugar
Properties
Density Index
0.80 g/cm3
1 Cup Weight
190g
Texture
Dry, fine crystals
Category
Sugars
Top Substitute
Granulated Sugar
Use 1:1 by weight
Works in almost everything. For meringues and delicate sponges, blitz granulated in a blender for 10-15 seconds first to approximate the finer crystal.
Most-used links for Caster Sugar
Conversions
| cups | grams |
|---|---|
| 1/4 cups | 48.0 grams |
| 1/3 cups | 63.0 grams |
| 1/2 cups | 95.0 grams |
| 1 cups | 190 grams |
| 1.50 cups | 285 grams |
| 2 cups | 380 grams |
| 3 cups | 570 grams |
| 4 cups | 760 grams |
Figures use the US cup (236.6 ml).
Density: 0.8 g/ml
Quick Convert
Ingredient-specific, density-based conversions for baking
1 cups of Caster Sugar equals 189 grams
Ingredient-specific · density-based
Cup size
Based on us cup (236.6 ml) · density data from baking references and our own measurements.What the sources say caster sugar weighs
Published values, quoted at the exact measure each source lists. Sources round differently and assume different fill techniques — which is why they rarely agree to the gram.
| Source | Listed measure | Weight |
|---|---|---|
| King Arthur Baking | 1 cup (Baker's Special / superfine) | 190 g |
| King Arthur Baking | 1 cup (granulated, for comparison) | 198 g |
CupOrGram standardizes on 190 g per cup (12 g per tablespoon, 4 g per teaspoon) and uses that single value on every page — how we reconcile the sources.
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Recommended Tools & Pantry Picks for Caster Sugar
Optional shopping references for bakers who want to compare tools and pantry options related to caster sugar.
Measuring Cup & Spoon Set
Useful for quick volume checks before converting to weight.
Shop measuring sets ↗Disclosure: Some outbound links are affiliate links. As an Amazon Associate, CupOrGram earns from qualifying purchases. Learn more.
Substitutions for Caster Sugar
Granulated Sugar
excellent1:1 by weight
Works in almost everything. For meringues and delicate sponges, blitz granulated in a blender for 10-15 seconds first to approximate the finer crystal.
Chemically identical sucrose; only crystal size differs. Coarser crystals dissolve slower, which can leave speckled meringue and slightly coarser crumb.
Powdered Sugar (Icing Sugar)
moderate1:1 by weight, only where sugar fully dissolves
Contains about 3% cornstarch — fine in icings and some doughs, wrong for creaming or meringue.
Particles are too fine to cut air pockets into butter during creaming, and the added starch changes texture in high-sugar recipes.
Storage Tips
Airtight container, cool and dry. Indefinite shelf life.
Baking Science
Crystal size sits between granulated and powdered: small enough to dissolve quickly into creamed butter and meringues (fewer undissolved specks, finer crumb), large enough to still aerate fat the way granulated does. King Arthur lists it at 190 g per cup versus 198 g for granulated — the finer crystals actually pack slightly lighter.
Recipe Context
For cookies: sugar ratio drives spread and caramelization.
For cakes: sugar level affects tenderness and moisture retention.
For frostings: weight gives repeatable texture batch to batch.
Common Pitfalls
- Switching brands without re-checking weight can change texture and bake time.
- Using volume-only measurements for dense ingredients can overshoot recipe targets.
- Packed vs unpacked sugar measurements are not interchangeable.
Brand Variance & Measuring Method
Baseline reference: 1 cup caster sugar = 190g. In real kitchens, a practical range is usually 175g-205g per cup (8% band).
Why this happens: granule size, packing, and moisture level shift how much sugar fits in a cup.
Figures use the US cup (236.6 ml).Common Questions
How many grams is 1 cup of caster sugar?
1 cup of caster sugar weighs 190 grams.
What can I substitute for caster sugar?
Granulated Sugar (1:1 by weight), Powdered Sugar (Icing Sugar) (1:1 by weight, only where sugar fully dissolves)
Explore Caster Sugar Further
Reference
See caster sugar in the full measurement table
Cup, tablespoon, and teaspoon weights for all ingredients, sourced and cross-checked.