Fluid Ounces of skim milk to grams runs on one number, 30.625 grams per fluid ounce. It is a measured property of this ingredient rather than a defined conversion, which is why a generic volume-to-weight tool cannot give you it.
Water is the yardstick: 1 mL of it weighs 1 g. Skim milk 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 skim milk 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 skim milk, 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: Marginally denser than whole milk, because the fat removed from it was the lightest part.
The formula
fluid ounces- The amount of skim milk you are converting, in fluid ounces
30.625- Grams per fluid ounce for skim milk, 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 skim milk.
- 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 skim milk in grams
A recipe calling for 3 fl oz of skim milk 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 skim milk in grams
6 fl oz of skim milk weighs out at 183.75 grams. Divide 183.75 by 30.625 and you get back to 6 fl oz, which is the quickest check that the factor is the right way up.
12 fl oz of skim milk in grams
Take 12 fl oz of skim milk: 12 × 30.625 gives 367.5 grams. Doubling the batch takes it to 735 grams, because the relationship is a straight proportion once the density is known.
How to read your score
Frequently asked questions
How many grams are in 1 fl oz of skim milk?
One fluid ounce of skim milk 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 skim milk not 236 g like water?
Because weight per cup depends on what is in the cup. Skim milk 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. Skim milk 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 skim milk 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 skim milk 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 skim milk 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 skim milk — 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 skim milk is 500 g?
500 g of skim milk 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.
Skim milk 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 skim milk. One fluid ounce of skim milk 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) |
|---|---|---|---|
| Half-and-half | 242 g | 8.536 oz | 1.023 |
| Egg whites | 243 g | 8.572 oz | 1.027 |
| Whole milk | 244 g | 8.607 oz | 1.031 |
| Skim milk (this page) | 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 | 245 g | 8.642 oz | 1.036 |
Ordered by weight. The spread across this group is why a single generic cups-to-grams factor cannot work.