One gram of onion powder is 2.057289 millilitres, so converting grams of onion powder to millilitres means multiplying by 2.057289. 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.
Onion powder has a density of 0.48608 g per mL, so 100 mL of it weighs 48.61 g and 250 mL weighs 121.5 g. That single figure is what every other number on this page is built from — water is 1.00 g per mL, so this ingredient is 48.61% as heavy as the same volume of water.
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.
The condition this weight assumes: Hygroscopic — it pulls in moisture and cakes, and a caked spoonful weighs more than a free-flowing one.
The formula
grams- The amount of onion powder you are converting, in grams
2.05728901304- Millilitres per gram for onion powder, from its density of 0.48608 g/mL
millilitres- The equivalent quantity in millilitres
How it works, step by step
- Enter the quantity in grams.
- It is multiplied by 2.05728901304, the millilitres-per-gram figure for onion powder.
- The result appears in millilitres, with a second reading in tsp beneath it.
- Use the measure table if you want a standard recipe quantity rather than a number you type in.
Worked examples
50 g of onion powder in millilitres
50 g of onion powder weighs out at 102.864 millilitres. Divide 102.864 by 2.057289 and you get back to 50 g, which is the quickest check that the factor is the right way up.
150 g of onion powder in millilitres
A recipe calling for 150 g of onion powder needs 308.593 millilitres on the scale. The arithmetic is 150 × 2.057289 = 308.59335, and halving the recipe halves the weight to 154.297 millilitres.
500 g of onion powder in millilitres
500 g of onion powder weighs out at 1028.64 millilitres. Divide 1028.64 by 2.057289 and you get back to 500 g, which is the quickest check that the factor is the right way up.
How to read your score
Frequently asked questions
How many millilitres are in 1 g of onion powder?
One gram of onion powder is 2.057289 millilitres. Half that quantity is 1.02864 millilitres and double it is 4.11458 millilitres, 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?
At this size the spoon wins. One millilitre of onion powder is 0.4861 g, and a scale reading to the nearest gram is working at 206% resolution on that — a measuring spoon is the more accurate instrument below about 5 g, which is why spice quantities are still written in spoons.
How much does 15 mL of onion powder weigh?
15 mL of onion powder comes to 7.2911 g, or 7.2911 grams. This page runs that calculation in reverse — enter a weight and it returns the volume — and the ml-to-grams page does it in the direction the question is usually asked.
Onion powder in grams and millilitres
| Grams | Millilitres | Unrounded |
|---|---|---|
| 5 g | 10.2864 mL | 10.28644507 |
| 10 g | 20.5729 mL | 20.57289013 |
| 25 g | 51.4322 mL | 51.43222533 |
| 50 g | 102.864 mL | 102.8644507 |
| 100 g | 205.729 mL | 205.7289013 |
| 125 g | 257.161 mL | 257.1611266 |
| 150 g | 308.593 mL | 308.593352 |
| 200 g | 411.458 mL | 411.4578026 |
| 250 g | 514.322 mL | 514.3222533 |
| 300 g | 617.187 mL | 617.1867039 |
| 500 g | 1028.64 mL | 1028.644507 |
| 1000 g | 2057.29 mL | 2057.289013 |
Based on 115 g per cup of onion powder. One gram of onion powder is 2.057289 millilitres.
| 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.