Cups to Grams: Water
1 cup of water is about 237 grams. Enter any amount to convert it.
How many grams are in a cup of water?
One US cup of water weighs about 237 grams (8.4 ounces). Half a cup is about 118 g, and one tablespoon is about 15 g.
A US cup of water is 8 fluid ounces, about 237 ml. Many recipes round this to 240 g, which is close enough for cooking.
Water conversion chart
| Volume | Grams | Ounces |
|---|---|---|
| ¼ cup | 59 g | 2.1 oz |
| ⅓ cup | 79 g | 2.8 oz |
| ½ cup | 118 g | 4.2 oz |
| ⅔ cup | 158 g | 5.6 oz |
| ¾ cup | 178 g | 6.3 oz |
| 1 cup | 237 g | 8.4 oz |
| 1½ cups | 356 g | 12.5 oz |
| 2 cups | 474 g | 16.7 oz |
| 1 tablespoon | 15 g | 0.5 oz |
| 1 teaspoon | 4.9 g | 0.2 oz |
Why 1 gram of water is 1 milliliter
The metric system was built around water: 1 milliliter of water weighs about 1 gram at room temperature, so 237 ml of water is 237 g. That makes water the easiest ingredient to convert. A US cup is 8 fluid ounces, or 236.6 ml. Recipes often round to 240 g, and in practice the 3 g difference does not matter.
Cups are not the same everywhere. The US legal cup used on nutrition labels is 240 ml, and the metric cup used in Australia, New Zealand and many other countries is 250 ml. A recipe from outside the US that says "1 cup of water" may therefore call for about 5 percent more than you pour from a US measuring cup.
Water in bread, starters and yeast
In bread recipes, water is the number everything else is measured against. A sourdough starter fed at 100 percent hydration uses equal weights of flour and water: 120 g of all-purpose flour (about 1 cup) with 120 g of water, just over ½ cup. Weighing the water is far more precise than reading a line on a measuring cup.
For active dry yeast, water around 105 to 110°F is warm but not hot, and water over about 130°F can kill the yeast. A small fact worth knowing: a US fluid ounce of water weighs about 1.04 ounces, which is why "a pint's a pound the world around" is close but not exact in the US. A pint of water is about 473 g, or 1.04 pounds.
Frequently asked questions
How many cups is 100 grams of water?
100 g of water is about 0.42 cups.
How many grams is a tablespoon of water?
About 15 g, based on 237 g per cup and 16 tablespoons per cup.
How many grams is a liter of water?
About 1,000 g, or 1 kg, at room temperature.
How many cups is 500 grams of water?
About 2.1 cups, since 500 g divided by 237 g is just over 2.
Does hot water weigh less than cold water?
Slightly, because water expands as it heats, but not by an amount that matters in cooking. A cup of near-boiling water weighs about 10 g less than a cup of cold water.