Cups of Rolled Oats to Grams
1 cup of rolled oats weighs 89 g (King Arthur Baking: "Oats (old-fashioned or quick-cooking): 1 cup = 89 g"), which makes oats one of the lightest things in your pantry. Steel-cut oats are a different animal at 140 g per cup, so never swap one for the other by volume.
Source: Oats (old-fashioned or quick-cooking): 1 cup = 89 g (King Arthur Baking, Ingredient Weight Chart). USDA lists 81 g (fdcId 173904).
| Cups | Grams (US cup) | Ounces (US cup) | Grams (metric cup, 250 ml) |
|---|---|---|---|
| 1/8 cup | 11 | 0.392 | 12 |
| 1/4 cup | 22 | 0.785 | 24 |
| 1/3 cup | 30 | 1.05 | 31 |
| 1/2 cup | 44 | 1.57 | 47 |
| 2/3 cup | 59 | 2.09 | 63 |
| 3/4 cup | 67 | 2.35 | 71 |
| 1 cup | 89 | 3.14 | 94 |
| 1 1/2 cups | 134 | 4.71 | 141 |
| 2 cups | 178 | 6.28 | 188 |
| 3 cups | 267 | 9.42 | 282 |
| 4 cups | 356 | 12.56 | 376 |
| Grams | US cups | Measuring-cup version |
|---|---|---|
| 25 g | 0.281 | about ¼ cup + 1 tsp |
| 50 g | 0.562 | ½ cup + 1 tbsp |
| 100 g | 1.12 | about 1 cup + 2 tbsp |
| 125 g | 1.4 | about 1 ⅓ cups + 1 tbsp |
| 150 g | 1.69 | about 1 ⅔ cups + 1 tsp |
| 200 g | 2.25 | about 2 ¼ cups |
| 250 g | 2.81 | about 2 ¾ cups + 1 tbsp |
| 300 g | 3.37 | about 3 ⅓ cups + 2 tsp |
| 400 g | 4.49 | about 4 ⅓ cups + 2 tbsp + 2 tsp |
| 500 g | 5.62 | about 5 ½ cups + 2 tbsp |
| 1,000 g | 11.24 | about 11 cups + 3 tbsp + 2 tsp |
| Measure | Grams | Milliliters |
|---|---|---|
| 1/4 tsp | 0.5 | 1.23 |
| 1/2 tsp | 0.9 | 2.46 |
| 1 tsp | 1.9 | 4.93 |
| 1 tbsp (3 tsp) | 5.6 | 14.79 |
| 2 tbsp (1/8 cup) | 11.1 | 29.57 |
| 4 tbsp (1/4 cup) | 22.2 | 59.15 |
| 8 tbsp (1/2 cup) | 44.5 | 118.3 |
Worked example: oatmeal cookies with 1 ½ cups rolled oats
- Per cup: 89 g.
- Multiply: 1.5 × 89 g = 134 g.
- Convert to ounces for a bulk-bin purchase: 133.5 ÷ 28.3 = 4.7 oz.
- Using the USDA figure: 1.5 × 81 g = 122 g, a gap of 12 g.
- If you had accidentally used steel-cut oats: 1.5 × 140 g = 210 g.
Rolled and quick-cooking oats
The King Arthur Baking entry covers both old-fashioned and quick-cooking oats under a single 89 g figure. Both are rolled flakes, so one cup weight serves for either. USDA FoodData Central lists 81 g, which is 8 g less, so two respected charts already differ by 10%.
Steel-cut oats are another ingredient
Steel-cut oats are whole groats chopped into pieces, so they are dense. A cup is 140 g, which is 1.57 times the weight of a cup of rolled oats. If a granola recipe calls for 4 cups of rolled oats, that is 356 g. The same four cups of steel-cut would be 560 g, 204 g extra, and it would come out gritty rather than crisp.
Oat flour sits in between
Grind rolled oats in a blender and the flour is 92 g per cup. That is 3 g more than the flakes you started with, since grinding closes the air gaps. A recipe that asks for oat flour cannot use a cup of whole flakes: weigh instead. Compare with wheat flour: a cup of all-purpose is 120 g, so oat flour is lighter by 28 g.
Cup measures versus a scale for oats
Oats are bulky and light, so a small difference in how the cup is filled becomes a large percentage difference. The two published cups above, 89 g and 81 g, are 8 g apart. In a granola with 6 cups of oats that gap grows to 48 g, enough to change how well the mix binds. A scale takes this problem away and costs almost nothing. For rice, another dry grain, see rice cups to grams.
Tips for baking and breakfast
- Flakes measure by loosely filling the cup; do not press them down.
- For porridge, follow the package's water ratio, because it depends on the cut of oat.
- Toast oats in a dry pan for cookies and bars to add a nutty note before weighing them.
- Measure oats in a dry cup, not a liquid jug; levelling flakes by eye is imprecise.
Overnight oats and single servings
Single-serving recipes use small amounts. Half a cup of rolled oats is 44.5 g, a third of a cup is 29.7 g and a quarter cup is 22.3 g. A tablespoon is 5.56 g, so a quarter cup is 4 tablespoons of oats.
Metric cup
In a 250 ml cup, rolled oats come to about 94.1 g (0.3762 g per ml × 250 ml).
Frequently asked questions
How many grams are in 1 cup of rolled oats?
1 US cup of rolled oats is 89 g (King Arthur Baking); USDA lists 81 g.
How many grams are in 1 cup of steel-cut oats?
1 cup of steel-cut oats is 140 g, much heavier than rolled oats.
Are quick oats the same weight as rolled oats?
King Arthur lists old-fashioned and quick-cooking oats together at 89 g per cup.
How many cups is 100 g of oats?
100 g of rolled oats is 1.12 cups, about 1 ⅛ cups.
Can I use oat flour in place of rolled oats?
Not by volume: oat flour is 92 g per cup compared with 89 g for flakes, and it behaves differently in dough.