Oats in grams, where one chart fights itself
Rolled oats weigh 89 grams to the US cup. The surprise is that the chart printing 89 also prints 113 two rows down for its own brand of oats, a 27 percent gap between two lines describing the same flake. Which number you want depends on whose oats are in your cupboard.
One chart, two weights for the same oats
King Arthur lists oats twice on a single page: 89 g for old-fashioned oats and 113 g for its own branded rolled oats. Nothing about the flake changed between the rows, only the label. We publish 89 g, the generic figure, for two reasons: it sits beside the USDA's 81 g, and a reader tipping oats from a supermarket canister is not holding King Arthur's product. The habit of naming the source behind each number is what the methodology page is built on.
| Which oats | A US cup |
|---|---|
| Old-fashioned, generic | 89 g |
| King Arthur, own brand | 113 g |
| USDA, dry oats | 81 g |
Oats conversions in full
Grams and ounces for the cup fractions a recipe asks for. A plain cup of oats in grams is the figure most people look up, and the rest scale from it. Going the other way, 100 grams of oats in cups spreads past a full cup.
| Rolled oats | Grams | Ounces |
|---|---|---|
| 1/4 cup | 22.3 g | 0.78 oz |
| 1/2 cup | 44.5 g | 1.6 oz |
| 3/4 cup | 66.8 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 |
Density used: 0.38 g per ml, for old-fashioned rolled oats.
The other oats: groats are not rolled oats
The USDA carries a second entry filed as oats, at 156 g per cup, and it is not the rolled oats a breakfast recipe means: it is whole groats, the intact grain before rolling. Match on the word oats alone and you publish a cup nearly twice the truth. This is why a chart cannot be read by its labels: the same word covers a flake you pour and a kernel you would never eat raw, and only the weight tells them apart.
A cup of oats abroad
A metric cup of rolled oats runs 90 to 105 g depending on the chart, the lighter figure from New Zealand's Healthy Food Guide and the heavier from Sanitarium, which sells oats. The Japanese standard tables weigh a 200 millilitre cup at 80 g, and only one Japanese table lists oatmeal at all, since it is a recent arrival to the Japanese kitchen rather than a staple with its own long-settled figure.
| Cup | Rolled oats |
|---|---|
| US customary | 89 g |
| Metric (250 ml) | 90 g |
| Japanese (200 ml) | 80 g |
Questions about oats weight
- How many grams is a cup of rolled oats?
- 89 g, the weight we publish for old-fashioned rolled oats. King Arthur's own branded oats read 113 on the same chart, so a recipe from that kitchen may mean the heavier cup.
- Do quick oats weigh the same as old-fashioned oats?
- Yes. Both King Arthur and the USDA file old-fashioned and quick-cooking oats in one row, because rolling a flake thinner spreads it wider without changing what it weighs. Steel-cut oats are a different shape and heavier per cup.
- Why does one chart list oats twice with different weights?
- King Arthur prints 89 g for generic old-fashioned oats and 113 for its own rolled oats, a 27 percent gap on one page. We take 89, the generic row, since it sits near the USDA's 81 and a supermarket canister is not the branded product.
Sources
King Arthur Baking for the 89 gram generic cup and the 113 gram branded cup, and the USDA FoodData Central SR Legacy for the 81 gram cup and the separate groats entry. Healthy Food Guide and Sanitarium for the metric cup. The Kagawa Nutrition University standard tables, as reproduced by Benricho, for the 80 gram Japanese cup. Full citations on the sources page.