One ounce of potato starch is 0.17718452 cups, so converting ounces of potato starch to cups means multiplying by 0.17718452. That factor is specific to this ingredient — it comes from its density, not from any relationship between the two units.
The density behind that figure is 0.67628 g per mL, against 1.00 for water. A cup of water weighs 236.6 g and a cup of potato starch weighs 160 g, so this ingredient is 67.63% as heavy as the same volume of water — the single fact the whole page rests on.
A cup of potato starch is 160 g when it is measured the standard way, but how it gets into the cup changes the answer: between about 144 g and 192 g covers the range from lightly spooned to firmly packed. That 20% spread is larger than most of the adjustments recipes fuss over, and it disappears entirely the moment the ingredient is weighed instead.
One cup of potato starch is 5.644 oz. US kitchen scales usually step in eighths of an ounce, which is 3.54 g — around 2.21% of a cup of this ingredient, so the scale is precise enough for a full cup and coarse for a spoonful. That is why recipes mix the two systems: ounces for the bulk, spoons for the small amounts.
The condition this weight assumes: Denser than cornstarch, and not the same product as potato flour despite the similar name.
The formula
ounces- The amount of potato starch you are converting, in ounces
0.177184519531- Cups per ounce for potato starch, from its density of 0.67628 g/mL
cups- The equivalent quantity in cups
How it works, step by step
- Enter the quantity in ounces.
- It is multiplied by 0.177184519531, the cups-per-ounce figure for potato starch.
- The result appears in cups, with a second reading in tbsp beneath it.
- Use the measure table if you want a standard recipe quantity rather than a number you type in.
Worked examples
2 oz of potato starch in cups
Take 2 oz of potato starch: 2 × 0.17718452 gives 0.354369 cups. Doubling the batch takes it to 0.708738 cups, because the relationship is a straight proportion once the density is known.
4 oz of potato starch in cups
4 oz of potato starch weighs out at 0.708738 cups. Divide 0.708738 by 0.17718452 and you get back to 4 oz, which is the quickest check that the factor is the right way up.
12 oz of potato starch in cups
A recipe calling for 12 oz of potato starch needs 2.12621 cups on the scale. The arithmetic is 12 × 0.17718452 = 2.1262142, and halving the recipe halves the weight to 1.06311 cups.
How to read your score
Frequently asked questions
How many cups are in 1 oz of potato starch?
One ounce of potato starch is 0.17718452 cups. Half that quantity is 0.0885923 cups and double it is 0.354369 cups, so the figure scales straight up and down — there is no offset in this conversion, only the factor.
Why is a cup of potato starch not 236 g like water?
Because weight per cup depends on what is in the cup. Potato starch has a density of 0.67628 g per mL where water has 1.00, so a cup of it weighs 160 g rather than 236.6 g. That is a difference of 76.6 g per cup, and it is the reason a single volume-to-weight factor cannot be applied to every ingredient.
Does how I measure it change the weight?
Yes, and by more than most people expect. Handling changes the weight of a cup of potato starch by roughly 20% — about 16 g either side of 160 g — because denser than cornstarch, and not the same product as potato flour despite the similar name. Weighing removes the question entirely.
Is a fluid ounce of potato starch the same as an ounce?
No. A fluid ounce is a volume — one eighth of a US cup, 29.57 mL — and an ounce is a weight. One fluid ounce of potato starch weighs 0.7055 oz, so the two readings differ by 29.5%. They coincide only for something with the density of water, and then only roughly.
Is this a US cup or a metric cup?
US customary: 236.59 mL, which is the cup every US recipe means. A metric cup is 250 mL, so the same cup of potato starch would weigh 169.07 g instead of 160 g — 9.07 g more, or 5.67%. Australian and some European recipes use the metric cup, and the difference is large enough to matter in baking.
Do I need a scale for this, or will measuring cups do?
A scale, if the result matters. Volume measuring carries a spread of about 20% for potato starch — roughly 32 g on a 160 g cup — while a domestic scale is accurate to a gram or two. For anything where the ratio of ingredients drives the outcome, bread and pastry above all, weigh it.
How much does 2 cup of potato starch weigh?
2 cup of potato starch comes to 320 g, or 11.288 ounces. This page runs that calculation in reverse — enter a weight and it returns the volume — and the cups-to-ounces page does it in the direction the question is usually asked.
Potato starch in ounces and cups
| Ounces | Cups | Unrounded |
|---|---|---|
| 1/2 oz | 0.0885923 cup | 0.08859225977 |
| 1 oz | 0.177185 cup | 0.1771845195 |
| 2 oz | 0.354369 cup | 0.3543690391 |
| 3 oz | 0.531554 cup | 0.5315535586 |
| 4 oz | 0.708738 cup | 0.7087380781 |
| 6 oz | 1.06311 cup | 1.063107117 |
| 8 oz | 1.41748 cup | 1.417476156 |
| 12 oz | 2.12621 cup | 2.126214234 |
| 16 oz | 2.83495 cup | 2.834952313 |
Based on 160 g per cup of potato starch. One ounce of potato starch is 0.17718452 cups.
| Measure | Grams | Ounces | Millilitres |
|---|---|---|---|
| 1 cup | 160 g | 5.64 oz | 236.6 mL |
| 3/4 cup | 120 g | 4.23 oz | 177.4 mL |
| 2/3 cup | 106.7 g | 3.76 oz | 157.7 mL |
| 1/2 cup | 80 g | 2.82 oz | 118.3 mL |
| 1/3 cup | 53.33 g | 1.88 oz | 78.86 mL |
| 1/4 cup | 40 g | 1.41 oz | 59.15 mL |
| 1 tbsp | 10 g | 0.353 oz | 14.79 mL |
| 1 tsp | 3.333 g | 0.118 oz | 4.929 mL |
US customary measures: 1 cup = 236.59 mL, 1 tbsp = 14.79 mL, 1 tsp = 4.93 mL.
| Ingredient | Grams per cup | Ounces per cup | Density (g/mL) |
|---|---|---|---|
| Cornmeal | 138 g | 4.868 oz | 0.5833 |
| Graham cracker crumbs | 142 g | 5.009 oz | 0.6002 |
| Rice flour | 158 g | 5.573 oz | 0.6678 |
| Potato starch (this page) | 160 g | 5.644 oz | 0.6763 |
| Steel-cut oats | 160 g | 5.644 oz | 0.6763 |
| Semolina | 167 g | 5.891 oz | 0.7059 |
| Uncooked quinoa | 170 g | 5.997 oz | 0.7185 |
Ordered by weight. The spread across this group is why a single generic cups-to-grams factor cannot work.