| US cup amount | Weight |
|---|---|
| 1/8 cup | 11 g |
| 1/4 cup | 22 g |
| 1/3 cup | 30 g |
| 1/2 cup | 44 g |
| 3/4 cup | 67 g |
| 1 cup | 89 g |
| 1 1/2 cups | 134 g |
| 2 cups | 178 g |
Oats Grams to Cups
1 US cup of rolled oats weighs 89 grams. One US cup of old-fashioned or quick-cooking oats weighs 89 grams. This value is for uncooked rolled oats, not steel-cut oats, prepared oatmeal, oat bran or oat flour.
Use the converter and charts below for old-fashioned or quick-cooking oats, uncooked.
Grams to Cups Converter
Choose the ingredient before converting because every ingredient has a different weight per cup.
Grams to Cups Converter
Results use the documented ingredient state and one US customary cup.
Divide the gram amount by 89 to calculate US cups. The practical fraction is a measuring aid, not a replacement for the exact gram weight.
| Grams | US cups | Practical reference |
|---|---|---|
| 25 g | 0.28 cups | about 1/4 cup |
| 30 g | 0.34 cups | about 1/3 cup |
| 40 g | 0.45 cups | about 1/2 cup |
| 50 g | 0.56 cups | about 1/2 cup |
| 60 g | 0.67 cups | about 2/3 cup |
| 75 g | 0.84 cups | about 7/8 cup |
| 80 g | 0.9 cups | about 7/8 cup |
| 100 g | 1.12 cups | about 1 1/8 cup |
| 120 g | 1.35 cups | about 1 1/3 cup |
| 125 g | 1.4 cups | about 1 3/8 cup |
| 150 g | 1.69 cups | about 1 2/3 cup |
| 200 g | 2.25 cups | about 2 1/4 cup |
| 250 g | 2.81 cups | about 2 3/4 cup |
| 300 g | 3.37 cups | about 3 3/8 cup |
| 400 g | 4.49 cups | about 4 1/2 cup |
| 500 g | 5.62 cups | about 5 5/8 cup |
Spoon or pour rolled oats into a dry cup and level the top without pressing. Large oat flakes leave natural air gaps, so a kitchen scale gives a more repeatable portion.
Grams = cups × 89
One cup is 89 grams, one-half cup is about 44 grams and one-quarter cup is about 22 grams.
Common uses
- Oatmeal and overnight oats
- Granola
- Cookies and crumble toppings
Rolled oats are light for their volume. Steel-cut oats are denser and cooked oatmeal contains absorbed water, so those products need separate conversions rather than a renamed version of this chart.
The converter does not assume that every cup weighs 237 or 250 grams. It uses the documented value for the exact ingredient and state selected.
If a product label or recipe publisher supplies a different gram weight for one cup, follow that recipe-specific value for the closest match to the original testing.
Method and source
How this conversion was checked
This page uses 89 grams per US cup for old-fashioned or quick-cooking oats, uncooked. Do not use this value for steel-cut oats or oat flour.
Primary reference: King Arthur Baking Ingredient Weight Chart
Cup standard: NIST US customary cup reference
How many grams are in one cup of rolled oats?
One US cup of old-fashioned or quick-cooking oats, uncooked uses a working reference of 89 grams on GramstoCup.co.
How many cups is 100 grams of rolled oats?
100 grams of old-fashioned or quick-cooking oats, uncooked is 1.12 US cups.
How many grams is half a cup of rolled oats?
Half a US cup is approximately 44 grams using the 89 gram full-cup reference.
Can the result vary by brand or method?
Yes. Do not use this value for steel-cut oats or oat flour. Use the original recipe weight when precision is important.
Are these US cups or metric cups?
The results use a US customary cup. A metric cup is 250 milliliters and can produce a different answer.
Other Ingredient Guides
Each guide uses its own grams-per-cup standard.
Editorial review
Reviewed for clarity and consistency
Written and reviewed by William Leo. Ingredient values are checked against the methodology and sources listed on this page.
Last reviewed
August 23, 2026