Grains, Rice & Legumes
Convert cups of rolled oats to ounces
One cup of rolled oats weighs about 3.17 oz, and half a cup comes to roughly 1.59 oz. Enter any amount below to convert it, or use the chart further down as a quick reference while you cook.
1 cup of rolled oats =
3.17 oz
- kg
- 0.09
- lb
- 0.198
Rolled Oats: 90 g per US cup · USDA FoodData Central. Old-fashioned rolled oats. Quick oats are cut smaller and measure closer to 100 g per cup.
Full rolled oats chart →Rolled Oats at a glance
Every number on this page comes from a single figure: 90 grams per US cup (USDA FoodData Central).
- 1 cup
- 90 g
- 1 tablespoon
- 5.63 g
- 1 teaspoon
- 1.88 g
- 1 cup in ounces
- 3.17 oz
- 100 g in cups
- 1.11 cups
- Density
- 0.38 g/ml
cups to ounces chart for rolled oats
Print it, screenshot it, or bookmark this page — these are the amounts recipes ask for most often.
| Cups (US) | Grams | Ounces (weight) | Pounds |
|---|---|---|---|
| 1/8 cup | 11.3 g | 0.397 oz | 0.025 lb |
| 1/4 cup | 22.5 g | 0.794 oz | 0.05 lb |
| 1/3 cup | 30 g | 1.06 oz | 0.066 lb |
| 1/2 cup | 45 g | 1.59 oz | 0.099 lb |
| 2/3 cup | 60 g | 2.12 oz | 0.132 lb |
| 3/4 cup | 67.5 g | 2.38 oz | 0.149 lb |
| 1 cup | 90 g | 3.17 oz | 0.198 lb |
| 1 1/2 cup | 135 g | 4.76 oz | 0.298 lb |
| 2 cup | 180 g | 6.35 oz | 0.397 lb |
| 3 cup | 270 g | 9.52 oz | 0.595 lb |
| 4 cup | 360 g | 12.7 oz | 0.794 lb |
How this conversion is calculated
Volume-to-weight conversions are only as good as the density behind them. We treat rolled oats as 90 g per US customary cup, which works out to 0.380 g/ml. From there:
- Your cups figure is converted into millilitres or grams using standard unit sizes (cup = 237 ml).
- The density above bridges volume and weight in whichever direction you need.
- The result is rounded the way a cook would round it — to the nearest gram, or to a usable fraction such as 1 1/8 cups.
Measuring rolled oats accurately
Old-fashioned rolled oats. Quick oats are cut smaller and measure closer to 100 g per cup.
If a recipe matters to you — bread, macarons, anything with a tight hydration or ratio — weigh it. A £10 digital scale removes the single largest source of variation in home baking, and it is faster than washing three measuring cups.
When cups are fine
- Liquids measured in a proper jug, where volume is the honest unit anyway.
- Forgiving savoury cooking: soups, stews, stir-fries, marinades.
- Small amounts of leaveners and spices, as long as you use level spoons.
Frequently asked questions
How many ounces are in 1 cup of rolled oats?
1 cup of rolled oats is 3.17 oz. This is based on a density of 90 g per US cup.
How many ounces are in 2 cups of rolled oats?
2 cups of rolled oats is 6.35 oz, and 1.59 oz for half a cup.
How much is 100 g of rolled oats in cups?
100 g of rolled oats is about 1 1/8 cups. Weight is always the more reliable measurement, so use a scale when the recipe gives grams.
Why do other sites give a different number for rolled oats?
Old-fashioned rolled oats. Quick oats are cut smaller and measure closer to 100 g per cup.
Do UK and Australian cups give the same result?
No. A US customary cup is 236.6 ml, a metric cup used in Australia and New Zealand is 250 ml, and an old UK imperial cup is 284 ml. Our default is the US cup, but you can pick metric cups in the converter.