How Many Grams in a Cup of Rolled Oats?
Updated September 25, 2026
1 US cup of rolled oats
89g
3.1 oz, scooped and leveled, not packed
- 1/2 cup
- 45 g
- 1/4 cup
- 22 g
- 1 tablespoon
- 5.6 g
- 1 teaspoon
- 1.9 g
One cup of old-fashioned rolled oats weighs about 89 grams (just over 3 ounces), and quick-cooking oats weigh about the same per cup. With oats, the product itself changes the weight: thick-cut and steel-cut oats weigh a lot more per cup.
Rolled Oats converter
Fractions work too, for example 1/3 or 1 1/2.
Cups to grams
| US cups | Grams | Ounces |
|---|---|---|
| 1/8 cup | 11 g | 0.39 oz |
| 1/4 cup | 22 g | 0.78 oz |
| 1/3 cup | 30 g | 1 oz |
| 1/2 cup | 45 g | 1.6 oz |
| 2/3 cup | 59 g | 2.1 oz |
| 3/4 cup | 67 g | 2.4 oz |
| 1 cup | 89 g | 3.1 oz |
| 1 1/2 cups | 134 g | 4.7 oz |
| 2 cups | 178 g | 6.3 oz |
| 3 cups | 267 g | 9.4 oz |
| 4 cups | 356 g | 12.6 oz |
Grams to cups
| Grams | Cups (decimal) | With measuring cups and spoons |
|---|---|---|
| 25 g | 0.28 | 1/4 cup + 1 1/2 tsp |
| 50 g | 0.56 | 1/2 cup + 1 tbsp |
| 100 g | 1.12 | 1 cup + 2 tbsp |
| 150 g | 1.69 | 1 2/3 cups + 1 tsp |
| 200 g | 2.25 | 2 1/4 cups |
| 250 g | 2.81 | 2 3/4 cups + 1 tbsp |
| 300 g | 3.37 | 3 1/3 cups + 2 tsp |
| 400 g | 4.49 | 4 1/3 cups + 2 tbsp + 1 1/2 tsp |
| 500 g | 5.62 | 5 1/2 cups + 1 tbsp + 2 1/2 tsp |
| 1,000 g | 11.24 | 11 cups + 3 tbsp + 2 1/2 tsp |
Oat types by weight
Using King Arthur Baking's figures, old-fashioned or quick oats weigh about 89 g per cup; King Arthur's own thicker rolled oats about 113 g per cup; steel-cut oats about 70 g per ½ cup, or roughly 140 g per cup; and oat flour about 92 g per cup.
Quick oats are rolled thinner and cut smaller than old-fashioned oats, so they cook faster and give cookies and muffins a softer texture.
Tips for measuring rolled oats
- Quick and old-fashioned rolled oats can usually be swapped in cookies, muffins and crisps. Steel-cut oats can't, because they stay firm unless cooked for much longer.
- Oats are naturally gluten-free but are often processed alongside wheat. If you're baking for someone with celiac disease, look for oats labeled certified gluten-free.
- To make oat flour, blend rolled oats until fine. Weigh the flour afterward rather than measuring by the cup, since grinding changes its volume.
Frequently asked questions
Are quick oats and rolled oats the same weight?
Per cup, about the same, roughly 89 g. The difference is texture: quick oats are thinner and smaller, so they soften faster in cooking and baking.
How many grams are in 1/2 cup of rolled oats?
Half a cup of rolled oats weighs about 45 grams (1.6 ounces).
How many cups is 100 grams of rolled oats?
100 g of rolled oats is about 1.12 US cups, which you can measure as 1 cup + 2 tbsp.
How many grams are in a tablespoon of rolled oats?
One tablespoon weighs about 5.6 g, and one teaspoon about 1.9 g.
More cups-to-grams conversions
See every ingredient side by side in the baking ingredient weight chart, or convert cups, spoons and milliliters with the kitchen unit converter.
Sources and method
The cup weight on this page comes from King Arthur Baking's Ingredient Weight Chart, which lists rolled oats as 1 cup (old-fashioned or quick-cooking) = 3 1/8 oz = 89 g. All other figures are calculated from that weight using a US customary cup (236.6 mL), 16 tablespoons per cup and 3 teaspoons per tablespoon. Using a 250 mL metric cup? Multiply the grams by about 1.06. Brand, humidity and measuring technique can shift real-world weights by a few percent, so weigh when precision matters.