Why grams change per cup

A cup measures volume, not weight. Because ingredients have different densities and pack differently, 1 cup will not weigh the same across ingredients. Flour is aerated and compressible; sugar is dense; butter has a near-fixed weight per cup.

Liquid vs dry measuring

• Dry ingredients: measure with dry cups/spoons and level off with a flat edge.
• Liquids: use a clear liquid measuring cup; read at eye level to avoid parallax error.
• Sticky liquids (honey, molasses) release easier if you lightly oil the cup.

US cup vs metric cup

The US cup is 236.588 ml; the metric cup is 250 ml. This tool assumes the US cup. Switching systems changes your grams per cup by a few percent—important in precision baking.

Spoon & level vs scooping

• Spoon & level (recommended): 1 cup all‑purpose flour ≈ 120 g.
• Scooping the bag: compacts flour; 1 cup can exceed 140 g, leading to dense, dry bakes.
• Sifted flour: aerated; expect slightly lower grams per cup.

Environment: humidity and altitude

• Humidity: flour absorbs moisture; grams per cup can creep up in humid climates.
• High altitude: lower air pressure affects rise and moisture; weighing ingredients improves consistency.

Substitutions change grams

• Swapping granulated for caster/superfine sugar alters packing and grams per cup.
• Almond vs coconut flour have very different densities; never use the same grams-per-cup.
• Packed brown sugar should be firmly pressed unless the recipe says “lightly packed.”

How to measure step‑by‑step

1. Fluff flour with a spoon; spoon into the cup without shaking.
2. Level with a straight edge (do not press down).
3. For brown sugar, pack firmly unless otherwise stated.
4. For liquids, set on a flat surface and read the meniscus at eye level.

Pro tips

• Use a digital scale (1 g resolution) for repeatable results.
• Record your own brand-specific densities if you bake frequently.
• When accuracy matters, convert recipes to grams and stick to weight.

Troubleshooting

• Cakes too dense: likely over-measured flour. Switch to spoon & level or weigh 120 g per cup.
• Cookies too thin: too little flour or warm butter. Recheck grams and chill dough.
• Bread too dry: too much flour. Verify cup standard (US vs metric) and humidity effects.