Flours & Starches
Convert cups of cornstarch to ounces
One cup of cornstarch weighs about 4.23 oz, and half a cup comes to roughly 2.12 oz. Enter any amount below to convert it, or use the chart further down as a quick reference while you cook.
1 cup of cornstarch =
4.23 oz
- kg
- 0.12
- lb
- 0.265
Cornstarch: 120 g per US cup · FAO / INFOODS density database. Cornstarch compacts in the box. Stir it before measuring or a level cup can weigh 135 g.
Full cornstarch chart →Cornstarch at a glance
Every number on this page comes from a single figure: 120 grams per US cup (FAO / INFOODS density database).
- 1 cup
- 120 g
- 1 tablespoon
- 7.5 g
- 1 teaspoon
- 2.5 g
- 1 cup in ounces
- 4.23 oz
- 100 g in cups
- 0.833 cups
- Density
- 0.51 g/ml
cups to ounces chart for cornstarch
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 | 15 g | 0.529 oz | 0.033 lb |
| 1/4 cup | 30 g | 1.06 oz | 0.066 lb |
| 1/3 cup | 40 g | 1.41 oz | 0.088 lb |
| 1/2 cup | 60 g | 2.12 oz | 0.132 lb |
| 2/3 cup | 80 g | 2.82 oz | 0.176 lb |
| 3/4 cup | 90 g | 3.17 oz | 0.198 lb |
| 1 cup | 120 g | 4.23 oz | 0.265 lb |
| 1 1/2 cup | 180 g | 6.35 oz | 0.397 lb |
| 2 cup | 240 g | 8.47 oz | 0.529 lb |
| 3 cup | 360 g | 12.7 oz | 0.794 lb |
| 4 cup | 480 g | 16.9 oz | 1.06 lb |
How this conversion is calculated
Volume-to-weight conversions are only as good as the density behind them. We treat cornstarch as 120 g per US customary cup, which works out to 0.507 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 7/8 cups.
Measuring cornstarch accurately
Cornstarch compacts in the box. Stir it before measuring or a level cup can weigh 135 g.
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 cornstarch?
1 cup of cornstarch is 4.23 oz. This is based on a density of 120 g per US cup.
How many ounces are in 2 cups of cornstarch?
2 cups of cornstarch is 8.47 oz, and 2.12 oz for half a cup.
How much is 100 g of cornstarch in cups?
100 g of cornstarch is about 7/8 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 cornstarch?
Cornstarch compacts in the box. Stir it before measuring or a level cup can weigh 135 g.
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.