A cup is a unit of volume, not weight — and different ingredients pack into that same volume very differently. A cup of all-purpose flour (light and airy) weighs about 120g, while a cup of granulated sugar (dense, fine crystals) weighs about 200g — nearly double, for the exact same cup.
How you fill the cup matters too: spooning flour in and leveling it gives a lighter, more accurate result than scooping directly from the bag, which packs the flour down and can add 20% or more extra weight. That single difference is enough to throw off a cake or bread recipe.
Weighing ingredients on a kitchen scale removes this source of error entirely — it's why most professional bakers and serious bread recipes specify weight instead of volume.
| Ingredient | 1 Cup (grams) | 1 Cup (oz) | 1 Tbsp (grams) |
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