How many grams in a cup of rolled oats?

1 cup of rolled oats weighs 89 g by King Arthur Baking's chart for old-fashioned or quick oats. USDA lists 81 g.

Sources: King Arthur Baking ingredient weight chart, USDA FoodData Central · Checked October 10, 2026

Amount

Unit

89 g 3.1 oz

Sources range from 81 g to 89 g for 1 cup.

Converting a whole recipe?

Sous Chef converts every ingredient in a recipe to grams and millilitres in one tap, rounded to amounts you would actually weigh.

Rolled oats cups to grams table

Using 89 g per US cup. A US cup is 236.6 mL; 1 cup is 16 tablespoons.

Rolled oats cups to grams
US cups	Grams	Ounces	Tablespoons
⅛ cup	11 g	0.4 oz	2
¼ cup	22 g	0.8 oz	4
⅓ cup	30 g	1 oz	5.3
½ cup	45 g	1.6 oz	8
⅔ cup	59 g	2.1 oz	10.7
¾ cup	67 g	2.4 oz	12
1 cup	89 g	3.1 oz	16
1½ cups	134 g	4.7 oz	24
2 cups	178 g	6.3 oz	32
3 cups	267 g	9.4 oz	48
4 cups	356 g	12.6 oz	64

Why sources disagree

Oat flakes leave a lot of air in the cup, and flake size varies by brand, so a cup can weigh anywhere in the 80s. King Arthur lists its own thicker rolled oats at 113 g per cup, which shows how much the flake matters.

Source	Listed as	Grams per cup
King Arthur Baking ingredient weight chart Oats (old-fashioned or quick-cooking)	1 cup = 89 g	89 g
USDA FoodData Central Cereals, oats, regular and quick, not fortified, dry	1 cup = 81 g	81 g

Bold row is the figure the calculator uses. Figures listed for a smaller measure are multiplied up to one cup.

How to measure rolled oats accurately

Spoon oats loosely into the cup and do not press them down.
Weigh on a digital scale when you can, since cup scoops vary from cook to cook.
If you use cups, fill the same way every time so your results stay consistent.

Convert the whole recipe, not one line

Converting a recipe one ingredient at a time is where mistakes slip in. Sous Chef imports a recipe from a link or pasted text, then converts every ingredient at once: dry ingredients and butter to grams, liquids to millilitres. Tap again to go back to cups.

US recipe

2¼ cups all-purpose flour
1 cup butter, softened
¾ cup brown sugar, packed
1½ cups milk

In Sous Chef, after "Convert to metric"

275 g all-purpose flour
225 g butter, softened
170 g brown sugar, packed
350 ml milk

Example output. Sous Chef rounds to amounts you would actually weigh, so its numbers can differ by a few grams from the table above.

Common questions

How many grams is half a cup of rolled oats?

Half a cup of rolled oats is about 45 g, using 89 g per cup.

How many grams is 1 tablespoon of rolled oats?

1 tablespoon of rolled oats is about 6 g, since 1 cup is 16 tablespoons and 89 g per cup divided by 16 is 6 g.

More conversions

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