Cups of skim milk to ounces runs on one number, 8.6421207 ounces per cup. 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.
The density behind that figure is 1.0356 g per mL, against 1.00 for water. A cup of water weighs 236.6 g and a cup of skim milk weighs 245 g, so this ingredient is 103.6% as heavy as the same volume of water — the single fact the whole page rests on.
A cup of skim milk is 245 g when it is measured the standard way, but how it gets into the cup changes the answer: between about 243.8 g and 247.4 g covers the range from lightly spooned to firmly packed. That 1% 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 skim milk is 8.642 oz. US kitchen scales usually step in eighths of an ounce, which is 3.54 g — around 1.45% 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: Marginally denser than whole milk, because the fat removed from it was the lightest part.
The formula
cups- The amount of skim milk you are converting, in cups
8.64212067765- Ounces per cup for skim milk, from its density of 1.0356 g/mL
ounces- The equivalent quantity in ounces
How it works, step by step
- Enter the quantity in cups.
- It is multiplied by 8.64212067765, the ounces-per-cup figure for skim milk.
- The result appears in ounces, with a second reading in g 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 skim milk in ounces
Take 1/3 cup of skim milk: 0.333333 × 8.6421207 gives 2.88071 ounces. Doubling the batch takes it to 5.76141 ounces, because the relationship is a straight proportion once the density is known.
3/4 cup of skim milk in ounces
A recipe calling for 3/4 cup of skim milk needs 6.48159 ounces on the scale. The arithmetic is 0.75 × 8.6421207 = 6.4815905, and halving the recipe halves the weight to 3.2408 ounces.
3 cup of skim milk in ounces
Take 3 cup of skim milk: 3 × 8.6421207 gives 25.9264 ounces. Doubling the batch takes it to 51.8527 ounces, because the relationship is a straight proportion once the density is known.
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Frequently asked questions
How many ounces are in 1 cup of skim milk?
One cup of skim milk is 8.6421207 ounces. Half that quantity is 4.32106 ounces and double it is 17.2842 ounces, 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 cups of skim milk is 16 oz?
16 oz of skim milk is 1.8514 cups — 0.115712 cups to one ounce, so 16 × 0.115712 = 1.8514. Going that way is a division by 8.64212, or a multiplication by 0.115712 if you prefer.
Skim milk in cups and ounces
| Cups | Ounces | Unrounded |
|---|---|---|
| 1/8 cup | 1.08027 oz | 1.080265085 |
| 1/4 cup | 2.16053 oz | 2.160530169 |
| 1/3 cup | 2.88071 oz | 2.880706893 |
| 1/2 cup | 4.32106 oz | 4.321060339 |
| 2/3 cup | 5.76141 oz | 5.761413785 |
| 3/4 cup | 6.48159 oz | 6.481590508 |
| 1 cup | 8.64212 oz | 8.642120678 |
| 1 1/2 cup | 12.9632 oz | 12.96318102 |
| 2 cup | 17.2842 oz | 17.28424136 |
| 3 cup | 25.9264 oz | 25.92636203 |
| 4 cup | 34.5685 oz | 34.56848271 |
Based on 245 g per cup of skim milk. One cup of skim milk is 8.6421207 ounces.
| 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.