100 grams of milk in cups
Milk is heavier than water, so 100 grams of it comes to about 0.41 of a US cup. That is a hair less than the same weight of water, and well under what the old eight-ounce rule would have you pour.
The eight-ounce rule undershoots milk
A charts convention holds that a cup of any liquid weighs eight ounces, 227 g, and King Arthur prints exactly that for milk. It is a rule about water, and milk is not water. The USDA weighed a cup of whole milk at 244 g. Read 100 g through the 227 g figure and you get 0.44 of a cup; read it through milk's real 244 g and you get 0.41. The rule hands you a fuller cup than you have.
| A cup of milk at | In US cups |
|---|---|
| USDA, 244 g | 0.41 |
| Water, 237 g | 0.42 |
| The eight-ounce rule, 227 g | 0.44 |
Milk against water
Milk carries dissolved sugar and protein, so it outweighs water: 244 g to the cup against water's 237. The gap is small and it runs the right way. 100 g of milk fills 0.41 of a cup, 100 g of water 0.42. Treat milk as water, the way the eight-ounce rule does, and you come up a little short in the jug. The milk master page sets the 227 g and 244 g figures side by side with the reason for the pick.
Other milk weights in cups
The same reading for the weights a recipe tends to name:
| Milk | US cups |
|---|---|
| 50 g | 0.20 cups |
| 100 g | 0.41 cups |
| 150 g | 0.61 cups |
| 200 g | 0.82 cups |
| 250 g | 1 cups |
The same 100 grams swings wide by ingredient. It is a sticky 0.29 of a cup for honey and an overflowing 1.1 cups of oats. Double it and 200 grams of milk is closer to four-fifths of a cup.
Questions about 100 grams of milk
- Is 100 grams of milk half a cup?
- No, less than half. Half a US cup of milk weighs about 122 g, so 100 g comes to roughly 0.41 of a cup.
- How many cups is 100 grams of milk?
- About 0.41 of a US cup, on the USDA's measured 244 g cup. Charts that read 0.44 are using the eight-ounce rule, which fits water, not milk.
- Why is a cup of milk heavier than a cup of water?
- Milk is water with sugar and protein dissolved in it, so the same volume weighs more: 244 g against water's 237. The Japanese tables show the same gap, milk running about five percent over water.
Sources
USDA FoodData Central SR Legacy for the 244 gram cup of whole milk, King Arthur Baking for the 227 gram eight-ounce figure it prints, and USDA again for water at 237 g. Full citations on the sources page.