Water: Grams to Cups

Why water is the one ingredient that converts exactly

Every other ingredient on this site has a cup weight that depends on how it was packed, sifted or stirred. Water does not. It fills the cup completely, has no air to trap and weighs 1 g per millilitre to within a fraction of a percent at kitchen temperatures, so grams and millilitres are the same number. A US customary cup is 236.6 ml, which is where the 237 g figure comes from — and it is the figure USDA FoodData Central records for a cup of water.

King Arthur Baking's chart lists 227 g (8 oz) for a cup of water. That is the old "a pint's a pound" rounding: it treats a cup as half a pound so the numbers stay tidy in ounces. The difference is 10 g per cup, about 4%. In bread dough that matters a little; in soup it does not. If a recipe was written with King Arthur's chart, use 227 g, otherwise use 237 g.

Which cup the recipe means

The cup itself changes more than the water does. A US cup is 236.6 ml. Australia, New Zealand, Canada and most metric recipes use a 250 ml cup, which holds 250 g of water. A US "legal" cup used on nutrition labels is 240 ml. Older British recipes sometimes mean an imperial half-pint, 284 ml. If a recipe gives water in grams and you want cups, 237 g is one US cup and 250 g is one metric cup.

For the amounts people convert most often: 100 g of water is about 0.42 US cups (just under ½ cup), 250 g is about 1.05 cups, 350 g is about 1.48 cups (just under 1½ cups) and 500 g is about 2.11 cups.

Measuring water for bread

Bread recipes written in grams usually express water as a percentage of the flour (hydration), so the water weight is the number that matters. Weigh it straight into the bowl on a zeroed scale; it is faster than filling a cup and more accurate. If you must use cups, use a clear liquid measuring cup on a flat counter and read the line at eye level — a dry measuring cup filled to the brim spills and usually comes up a few grams short.

Temperature changes the weight of a cup of water by well under 1% between cold tap water and warm water for yeast, so it is safe to ignore for conversions.

Where the 237 g figure comes from

• USDA FoodData Central: 1 cup of “Water, bottled, generic” = 237 g (FDC ID 174158)
• King Arthur Baking ingredient weight chart: Water, 1 cup = 227 g (chart)

This site uses 237 g per US cup of water, spooned and levelled. References checked September 2026.

How many cups is X grams of water?

How to measure water accurately

The 237 g figure assumes the spooned-and-levelled method: spoon the water into a dry measuring cup and sweep the top flat with a straight edge. Scooping the cup through the bag compacts it and gives a heavier cup.

• 1 US cup of water = 237 g
• 1 metric cup (250 ml) of water = 250 g
• ¾ cup = 178 g
• ½ cup = 119 g
• ⅓ cup = 79 g
• ¼ cup = 59 g
• 1 tablespoon = 14.8 g

Frequently asked questions

How many cups is 100 grams of water?

100 grams of water is about ⅜ US cups, based on 237 g per cup, or ⅜ metric cups.

How many grams in a cup of water?

One US cup of water weighs 237 grams. A 250 ml metric cup holds 250 grams.

How many cups is 250 grams of water?

250 grams of water is about 1.05 US cups, or 1 metric cups.

Does a UK cup of water weigh the same as a US cup?

No. A UK, Australian or Canadian metric cup is 250 ml against the US 236.6 ml, so it holds about 5.7% more — 250 g of water rather than 237 g.

How many tablespoons is 100 grams of water?

100 grams of water is about 6.75 tablespoons.

How many cups is 100 g of water?

About 0.42 US cups — just under ½ cup. 100 g of water is exactly 100 ml.

How many cups is 350 g of water?

About 1.48 US cups, so just under 1½ cups. In metric 250 ml cups it is 1.4 cups.

Is a cup of water 237 g or 250 g?

237 g in a US cup (236.6 ml). 250 g in a metric cup (250 ml), which Australian, New Zealand and Canadian recipes use.