To convert fluid ounces of tomato sauce into grams, multiply by 30.625: one fluid ounce comes to 30.625 grams. Every ingredient has its own figure here, because the units are measuring different things and only the density links them.
Water is the yardstick: 1 mL of it weighs 1 g. Tomato sauce comes in at 1.0356 g per mL, or 103.6% of water, which is why a cup of it is 245 g rather than 236.6 g. Volume and weight only line up for water, and only in metric.
This is the pair that catches people out. A fluid ounce is a volume and an ounce is a weight, and they are only the same number for something with the density of water. One fluid ounce of tomato sauce weighs 1.08 oz, so the two readings differ by 8.03% — worth knowing before trusting a recipe that just says "oz".
Grams are the unit this conversion is really for. A domestic scale resolves to a gram, which is 0.408% of a cup of tomato sauce, so weighing gets an accuracy no measuring cup can reach. A 500 g pack of it is 2.041 cups, and a 1 kg pack 4.082.
What the number depends on: Plain passata or smooth sauce, not paste. Concentrated tomato paste is considerably heavier per cup because most of the water has been driven off, so the two are not interchangeable by volume.
The formula
fluid ounces- The amount of tomato sauce you are converting, in fluid ounces
30.625- Grams per fluid ounce for tomato sauce, from its density of 1.0356 g/mL
grams- The equivalent quantity in grams
How it works, step by step
- Enter the quantity in fluid ounces.
- It is multiplied by 30.625, the grams-per-fluid ounce figure for tomato sauce.
- 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
3 fl oz of tomato sauce in grams
A recipe calling for 3 fl oz of tomato sauce needs 91.875 grams on the scale. The arithmetic is 3 × 30.625 = 91.875, and halving the recipe halves the weight to 45.9375 grams.
6 fl oz of tomato sauce in grams
Take 6 fl oz of tomato sauce: 6 × 30.625 gives 183.75 grams. Doubling the batch takes it to 367.5 grams, because the relationship is a straight proportion once the density is known.
12 fl oz of tomato sauce in grams
12 fl oz of tomato sauce weighs out at 367.5 grams. Divide 367.5 by 30.625 and you get back to 12 fl oz, 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 fl oz of tomato sauce?
One fluid ounce of tomato sauce is 30.625 grams. Half that quantity is 15.3125 grams and double it is 61.25 grams, so the figure scales straight up and down — there is no offset in this conversion, only the factor.
Why is a cup of tomato sauce not 236 g like water?
Because weight per cup depends on what is in the cup. Tomato sauce has a density of 1.0356 g per mL where water has 1.00, so a cup of it weighs 245 g rather than 236.6 g. That is a difference of 8.4 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?
Barely. Tomato sauce does not compress, so a cup of it is 245 g however it is poured — within about 1%, which is inside the accuracy of a domestic scale. This is the group where measuring by volume is defensible.
Is a fluid ounce of tomato sauce 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 tomato sauce weighs 1.08 oz, so the two readings differ by 8.03%. 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 tomato sauce would weigh 258.89 g instead of 245 g — 13.9 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 1% for tomato sauce — roughly 2.45 g on a 245 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 fluid ounces of tomato sauce is 500 g?
500 g of tomato sauce is 16.327 fluid ounces — 0.0326531 fluid ounces to one gram, so 500 × 0.0326531 = 16.327. Going that way is a division by 30.625, or a multiplication by 0.0326531 if you prefer.
Tomato sauce in fluid ounces and grams
| Fluid Ounces | Grams | Unrounded |
|---|---|---|
| 1 fl oz | 30.625 g | 30.625 |
| 2 fl oz | 61.25 g | 61.25 |
| 3 fl oz | 91.875 g | 91.875 |
| 4 fl oz | 122.5 g | 122.5 |
| 6 fl oz | 183.75 g | 183.75 |
| 8 fl oz | 245 g | 245 |
| 12 fl oz | 367.5 g | 367.5 |
| 16 fl oz | 490 g | 490 |
Based on 245 g per cup of tomato sauce. One fluid ounce of tomato sauce is 30.625 grams.
| Measure | Grams | Ounces | Millilitres |
|---|---|---|---|
| 1 cup | 245 g | 8.64 oz | 236.6 mL |
| 3/4 cup | 183.8 g | 6.48 oz | 177.4 mL |
| 2/3 cup | 163.3 g | 5.76 oz | 157.7 mL |
| 1/2 cup | 122.5 g | 4.32 oz | 118.3 mL |
| 1/3 cup | 81.67 g | 2.88 oz | 78.86 mL |
| 1/4 cup | 61.25 g | 2.16 oz | 59.15 mL |
| 1 tbsp | 15.31 g | 0.54 oz | 14.79 mL |
| 1 tsp | 5.104 g | 0.18 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) |
|---|---|---|---|
| Skim milk | 245 g | 8.642 oz | 1.036 |
| Buttermilk | 245 g | 8.642 oz | 1.036 |
| Plain yogurt | 245 g | 8.642 oz | 1.036 |
| Tomato sauce (this page) | 245 g | 8.642 oz | 1.036 |
| Orange juice | 248 g | 8.748 oz | 1.048 |
| Evaporated milk | 252 g | 8.889 oz | 1.065 |
| Peanut butter | 258 g | 9.101 oz | 1.091 |
Ordered by weight. The spread across this group is why a single generic cups-to-grams factor cannot work.