Weight vs volume: why your cup is lying to you
A “cup” measures volume (space), not mass (how much is actually there) — and for dry ingredients those two things drift apart fast.
Flour is the worst offender. Scoop a cup straight from the bag and you compress it; a cup of packed flour can weigh 150 g or more. Spoon it in gently and level it off and the same cup weighs about 125 g. That is a 20–30% difference in the most important ingredient in the recipe — enough to turn tender cookies into dry hockey pucks.
Weighing removes the variable entirely. 125 grams is 125 grams no matter who measures it, which is why every professional bakery and serious recipe works in grams. A €10 digital scale is the highest-return tool in baking.
If you take one thing from this guide: buy a digital scale and weigh your flour. It fixes more baking problems than any other single change.
How to measure flour correctly (without a scale)
If you must use cups, use the “spoon and level” method — it is the closest you can get to the weight most recipes assume:
- Fluff the flour in the bag or canister with a spoon so it is not packed.
- Spoon it lightly into the measuring cup, overfilling slightly. Never scoop with the cup itself.
- Level the top with the flat back of a knife. Do not tap or pack.
This gives roughly 125 g per cup of all-purpose flour — the standard most recipes are written around. Scooping straight from the bag can add 20–30 g per cup, which compounds quickly in a recipe with three or four cups.
Tapping the cup to “settle” the flour packs it down and adds weight — the opposite of what you want. Resist the urge.
A cup is not a cup: US, metric and UK differences
Measuring cups are not standardized worldwide, which is why recipes from different countries can clash:
| Standard | Volume | Notes |
|---|---|---|
| US customary cup | 236.6 ml | Used in most American recipes |
| US “legal” cup | 240 ml | Used on US nutrition labels |
| Metric cup | 250 ml | Australia, NZ, Canada, much of Europe |
| UK / imperial cup | 284 ml | Older British recipes (rare today) |
The practical takeaway: a metric cup is about 6% bigger than a US cup, and tablespoons differ too — a US tablespoon is 14.8 ml but an Australian one is 20 ml. For small quantities of leavening this matters. When in doubt, weigh.
Master gram-per-cup chart
Because weight depends on the ingredient, the same cup weighs very different amounts. These are the standard densities used across this site and in most recipes:
| Ingredient | Grams / cup | Grams / tbsp |
|---|---|---|
| All-purpose flour | 125 g | 8 g |
| Bread flour | 130 g | 8 g |
| Cake flour | 114 g | 7 g |
| Granulated sugar | 200 g | 12.5 g |
| Brown sugar (packed) | 220 g | 14 g |
| Powdered sugar | 120 g | 7.5 g |
| Butter | 227 g | 14 g |
| Vegetable oil | 218 g | 13.5 g |
| Honey | 340 g | 21 g |
| Cocoa powder | 118 g | 7.5 g |
| Rolled oats | 90 g | 5.5 g |
| Chocolate chips | 170 g | 11 g |
Notice butter (227 g) weighs almost double the same cup of flour (125 g). This is exactly why a generic “1 cup = 240 ml” converter gets baking wrong — and why our tools weigh each ingredient by type.
Dry vs liquid measuring cups
They measure the same volume but are designed for different jobs. Dry cups are meant to be filled to the brim and leveled. Liquid cups (clear, with a spout and lines) let you pour to a line at eye level without spilling.
Using a dry cup for liquids tends to overfill (you fill until it looks full); using a liquid cup for flour makes leveling impossible. For the most accuracy with either, weigh instead — 1 cup of water is 240 g, and our converters handle the rest.