How many carbs are in oats?
Oats has 26.5 g of total carbs per 1/2 cup dry (40 g) — about 22.3 g net carbs after 4.2 g of fiber. That's 66.3 g of carbs per 100 g, roughly 10% of the 275 g Daily Value.
USDA FoodData Central · dry rolled/old-fashioned · FDC 169705
Carbs by portion
| Portion | Total carbs | Net carbs | Fiber | Sugar | Calories |
|---|---|---|---|---|---|
| 1/2 cup dry (40 g) | 26.5 g | 22.3 g | 4.2 g | — | 156 |
| 100 g | 66.3 g | 55.7 g | 10.6 g | — | 389 |
| 1 oz (28 g) | 18.8 g | 15.8 g | 3 g | — | 110 |
Net carbs = total carbs − fiber (the carbs that raise blood sugar, used in keto/low-carb tracking). Values computed from USDA per-100 g data (FDC 169705, SR Legacy). dry rolled/old-fashioned.
A standard serving of oats has about 26.5 g of total carbs per 1/2 cup dry (40 g), which works out to 66.3 g per 100 g. That per-100 g figure looks alarming, and it’s the source of a lot of confusion — almost nobody eats 100 g of oats. That’s roughly 1 1/4 cups of dry oats, a much bigger bowl than most people pour. These USDA values are for dry oats, so the honest move is to anchor on the real scoop: a 1/2 cup dry, about 40 g. Cooking only adds water; it doesn’t add or remove a single gram of carbohydrate.
Why net carbs run below the total
The number that matters for keto, low-carb and blood-sugar tracking is net carbs — total carbs minus fiber. This is where oats separate themselves from refined grains. A 1/2-cup dry serving brings about 4.2 g of fiber, including beta-glucan, the soluble fiber oats are famous for, which pulls the net carbs down to roughly 22.3 g. With white rice or white bread, fiber barely moves the number; with oats it takes a real bite out of it. That same fiber is why oats digest slowly and raise blood sugar more gently than their carb count alone would suggest.
How oats fit a daily budget
In practical terms, oats are carb-dense by dry weight but fiber-rich, which makes them excellent fuel rather than a low-carb food. On a strict keto plan (20–50 g net carbs a day), even a single 1/2-cup serving at ~22.3 g net can claim most of the allowance, so oats don’t fit true keto. On a moderate or diabetic-friendly plan they’re a strong choice — the beta-glucan is well-studied for steadier blood sugar and lower LDL cholesterol — as long as you keep the portion honest and lean on whole rolled or steel-cut oats over sugary instant packets.
If you want the protein side of the picture, see protein in oats — and for any packaged oatmeal or oat product, read the label’s own carb and fiber lines, since added sugar can change the math fast.
Packaged oats & oatmeal options, graded
Prefer something off the shelf? Here are the best-graded oats & oatmeal in our catalog — each scored on our transparent Labelgrade. Check the carb line on each label for your goal.
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Labelgrade 80/100 · 31 g carbs · 12 g protein
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Frequently Asked Questions
How many carbs are in a serving of oats?
About 26.5 g of total carbohydrate in a 1/2-cup dry serving (40 g), the scoop most people actually eat. That's 66.3 g per 100 g of dry oats (USDA FDC 169705) — but 100 g is roughly 1 1/4 cups dry, far more than a normal bowl, so always anchor to the real serving.
What are the net carbs in oats?
About 22.3 g net carbs per 1/2-cup dry serving — total carbs (26.5 g) minus fiber (4.2 g). Oats are unusually high in fiber for a grain, including beta-glucan, so the net carbs run a few grams below the total instead of tracking it almost exactly the way refined grains do.
Are oats keto or low-carb?
No. Even a modest 1/2-cup dry serving is about 22.3 g net carbs, which can use up most of a strict 20–50 g daily keto budget on its own. Oats are an excellent steady-energy, high-fiber food, but they are not a low-carb one. On keto, people swap in chia or flax 'noatmeal' instead.
Do oats spike blood sugar?
More gently than most grains, thanks to the beta-glucan fiber that slows digestion — but they still raise it, because oats are carb-dense. Whole rolled or steel-cut oats blunt the rise better than instant; portion size and what you add (milk, yogurt, nuts) matter as much as the oats themselves.
Do oats have more carbs than rice?
Gram for gram, dry oats look higher (66.3 g per 100 g vs about 28 g for cooked rice), but that's a dry-vs-cooked mismatch — dry oats absorb water and expand. The fairer point is fiber: oats carry far more of it than white rice, so a serving's net carbs are buffered in a way rice's simply aren't.
When was this data last verified?
2026-06-04, against USDA FoodData Central FDC 169705 (Oats; SR Legacy). We re-verify reference pages periodically and update when USDA revises its values.
Whole-food values are USDA reference data, not a Labelgrade (that score is for branded packaged products). See our methodology and the macro calculator to turn this into a daily target.