One cup of onion powder is 115 grams, so converting cups of onion powder to grams means multiplying by 115. That factor is specific to this ingredient — it comes from its density, not from any relationship between the two units.
Put next to water — 1 g per mL exactly — onion powder measures 0.48608 g per mL. That ratio, 48.61%, is what separates this page from every other ingredient in the same units, and it is measured rather than defined.
A cup of onion powder is 115 g when it is measured the standard way, but how it gets into the cup changes the answer: between about 103.5 g and 138 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.
Grams are the unit this conversion is really for. A domestic scale resolves to a gram, which is 0.87% of a cup of onion powder, so weighing gets an accuracy no measuring cup can reach. A 500 g pack of it is 4.348 cups, and a 1 kg pack 8.696.
What the number depends on: Hygroscopic — it pulls in moisture and cakes, and a caked spoonful weighs more than a free-flowing one.
The formula
cups- The amount of onion powder you are converting, in cups
115- Grams per cup for onion powder, from its density of 0.48608 g/mL
grams- The equivalent quantity in grams
How it works, step by step
- Enter the quantity in cups.
- It is multiplied by 115, the grams-per-cup figure for onion powder.
- The result appears in grams, with a second reading in oz beneath it.
- Use the measure table if you want a standard recipe quantity rather than a number you type in.
Worked examples
1/3 cup of onion powder in grams
Take 1/3 cup of onion powder: 0.333333 × 115 gives 38.3333 grams. Doubling the batch takes it to 76.6667 grams, because the relationship is a straight proportion once the density is known.
3/4 cup of onion powder in grams
3/4 cup of onion powder weighs out at 86.25 grams. Divide 86.25 by 115 and you get back to 3/4 cup, which is the quickest check that the factor is the right way up.
3 cup of onion powder in grams
3 cup of onion powder weighs out at 345 grams. Divide 345 by 115 and you get back to 3 cup, which is the quickest check that the factor is the right way up.
How to read your score
Frequently asked questions
How many grams are in 1 cup of onion powder?
One cup of onion powder is 115 grams. Half that quantity is 57.5 grams and double it is 230 grams, so the figure scales straight up and down — there is no offset in this conversion, only the factor.
Why is a cup of onion powder not 236 g like water?
Because weight per cup depends on what is in the cup. Onion powder has a density of 0.48608 g per mL where water has 1.00, so a cup of it weighs 115 g rather than 236.6 g. That is a difference of 121.6 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 onion powder by roughly 20% — about 11.5 g either side of 115 g — because hygroscopic — it pulls in moisture and cakes, and a caked spoonful weighs more than a free-flowing one. Weighing removes the question entirely.
Is a fluid ounce of onion powder 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 onion powder weighs 0.5071 oz, so the two readings differ by 49.3%. 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 onion powder would weigh 121.52 g instead of 115 g — 6.52 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 onion powder — roughly 23 g on a 115 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 many cups of onion powder is 500 g?
500 g of onion powder is 4.3478 cups — 0.00869565 cups to one gram, so 500 × 0.00869565 = 4.3478. Going that way is a division by 115, or a multiplication by 0.00869565 if you prefer.
Onion powder in cups and grams
| Cups | Grams | Unrounded |
|---|---|---|
| 1/8 cup | 14.375 g | 14.375 |
| 1/4 cup | 28.75 g | 28.75 |
| 1/3 cup | 38.3333 g | 38.33333333 |
| 1/2 cup | 57.5 g | 57.5 |
| 2/3 cup | 76.6667 g | 76.66666667 |
| 3/4 cup | 86.25 g | 86.25 |
| 1 cup | 115 g | 115 |
| 1 1/2 cup | 172.5 g | 172.5 |
| 2 cup | 230 g | 230 |
| 3 cup | 345 g | 345 |
| 4 cup | 460 g | 460 |
Based on 115 g per cup of onion powder. One cup of onion powder is 115 grams.
| Measure | Grams | Ounces | Millilitres |
|---|---|---|---|
| 1 cup | 115 g | 4.06 oz | 236.6 mL |
| 1 tbsp | 7.188 g | 0.254 oz | 14.79 mL |
| 2 tsp | 4.792 g | 0.169 oz | 9.858 mL |
| 1 tsp | 2.396 g | 0.0845 oz | 4.929 mL |
| 3/4 tsp | 1.797 g | 0.0634 oz | 3.697 mL |
| 1/2 tsp | 1.198 g | 0.0423 oz | 2.464 mL |
| 1/4 tsp | 0.599 g | 0.0211 oz | 1.232 mL |
| 1/8 tsp | 0.2995 g | 0.0106 oz | 0.6161 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) |
|---|---|---|---|
| Ground nutmeg | 106 g | 3.739 oz | 0.448 |
| Ground black pepper | 110 g | 3.88 oz | 0.4649 |
| Paprika | 110 g | 3.88 oz | 0.4649 |
| Onion powder (this page) | 115 g | 4.057 oz | 0.4861 |
| Ground cinnamon | 125 g | 4.409 oz | 0.5283 |
| Chili powder | 125 g | 4.409 oz | 0.5283 |
| Garlic powder | 134 g | 4.727 oz | 0.5664 |
Ordered by weight. The spread across this group is why a single generic cups-to-grams factor cannot work.