Cups to Grams for Baking: Flour, Sugar & Butter Charts

A cup is a volume, not a weight

The US customary cup is defined as a volume of about 240 mL. When a recipe says "1 cup," it is telling you how much space the ingredient fills, not how heavy it is. That is fine for liquids, where volume and weight track closely, but it becomes a problem for dry goods that can be loose or packed.

This is why professional bakers weigh their ingredients. A digital kitchen scale removes the guesswork: 120 g of flour is always 120 g, whether you scooped it, spooned it, or sifted it first. Converting your favorite cup recipes to grams once, then working from the weights, gives you consistent results every single time.

Cup-to-gram charts for common ingredients

Here are reliable weights for 1 cup of the most common baking staples: all-purpose flour ≈ 4.25 oz (120 g); bread flour ≈ 4.5 oz (130 g); granulated white sugar ≈ 7 oz (200 g); packed brown sugar ≈ 7.5 oz (215 g); powdered (confectioners') sugar ≈ 4 oz (120 g); butter ≈ 8 oz (227 g); and milk ≈ 8.5 oz (240 g).

Notice that flour and powdered sugar weigh far less per cup than granulated sugar, even though all three are white powders. Powdered sugar is airy and packs light; granulated sugar is dense. This is exactly why you cannot swap ingredients cup-for-cup by weight — each has its own density, and a converter that knows the ingredient does the math for you.

How to measure flour accurately

If you must use cups, use the spoon-and-level method: fluff the flour, spoon it loosely into the cup, and sweep the top flat with a knife. Never scoop the cup straight into the bag — that compacts the flour and can add 20 to 30 g extra, enough to make cookies dry or cakes dense.

The surest fix is a scale. Set your bowl on it, press tare to zero, and add flour until the display reads the target grams. It is faster than leveling cups, uses fewer dishes, and — most importantly — makes your bakes repeatable. Once you weigh, you will rarely go back to cups for dry ingredients.

Frequently asked questions

How many grams is 1 cup of flour?

About 4.25 oz (120 g) of all-purpose flour, when measured with the spoon-and-level method. Scooped straight from the bag it can reach 5.3 oz (150 g), which is why weighing is more reliable.

Why is sugar heavier per cup than flour?

Granulated sugar crystals pack together densely with little air between them, so a cup holds more mass — about 7 oz (200 g) — than the same cup of light, airy flour at 4.25 oz (120 g).

Can I convert cups to grams without knowing the ingredient?

No — because grams measure weight and cups measure volume, you need the ingredient's density. One cup of flour, sugar, and butter all weigh different amounts, so pick the ingredient in the converter first.

Is a US cup the same as a metric cup?

Not quite. A US cup is about 240 mL, while the metric cup used in Australia and elsewhere is 250 mL. For most baking the 10 mL gap is small, but for precise work convert from the exact cup your recipe assumes.