How many grams is 1 cup of water?

One US cup of water weighs approximately 236.6 grams (236.588 ml). One metric cup equals 250 grams, and one imperial (UK) cup equals about 284.1 grams.

Why does the cup size differ between countries?

The US customary cup is defined as 8 US fluid ounces (236.588 ml). The metric cup, used in Australia, Canada, and other countries, is exactly 250 ml. The imperial cup, used historically in the UK, is 10 imperial fluid ounces (284.1 ml).

How many grams is 2 cups of water?

Two US cups of water weigh approximately 473 grams. Two metric cups equal 500 grams, and two imperial cups equal about 568 grams.

Is 1 cup of water exactly 240 ml?

The precise US cup is 236.588 ml. In practice many cooks round this to 240 ml, which introduces an error of about 1.4%. For baking where precision matters, use 236.6 ml or simply weigh the water on a scale.

Does water temperature affect the weight?

Yes, but only slightly. At 20 °C water is 0.998 g/ml; at 100 °C it drops to 0.958 g/ml. For all practical cooking and baking purposes, 1 ml = 1 g is accurate enough.

How many grams is 1/2 cup of water?

Half a US cup of water is approximately 118.3 grams. Half a metric cup is 125 grams, and half an imperial cup is about 142 grams.

Water Cups to Grams Converter

Name: Water Cups to Grams Converter
Availability: InStock
Author: Nham Vu

Convert US, metric, or imperial cups of water to grams and milliliters instantly — ideal for baking, cooking, and hydration tracking.

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Enter a water amount above and click Convert.

US Cup Quick Reference

1 US cup = 236.588 ml. Water density = 1 g/ml at 20 °C.

US Cups	Tbsp	ml	Grams	Fl oz
1/4 cup	4	59.1	59.1 g	2 fl oz
1/3 cup	5 1/3	78.9	78.9 g	2.7 fl oz
1/2 cup	8	118.3	118.3 g	4 fl oz
2/3 cup	10 2/3	157.7	157.7 g	5.3 fl oz
3/4 cup	12	177.4	177.4 g	6 fl oz
1 cup	16	236.6	236.6 g	8 fl oz
1 1/2 cups	24	354.9	354.9 g	12 fl oz
2 cups	32	473.2	473.2 g	16 fl oz
4 cups	64	946.4	946.4 g	32 fl oz

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Summary

Convert US, metric, or imperial cups of water to grams and milliliters instantly — ideal for baking, cooking, and hydration tracking.

How it works

Select the cup standard you are using — US cup, metric cup, or imperial cup.
Enter the number of cups (or click a quick-pick fraction button).
Click Convert to see the equivalent weight in grams and volume in milliliters.
View the full breakdown across all common units in the results grid.
Copy any individual result to your clipboard with one click.
Refer to the quick-reference table for the most common cup amounts.

Use cases

Weigh water precisely when a recipe lists cups but you use a kitchen scale.
Convert a US recipe's water amount to milliliters for a metric recipe.
Measure drinking water by weight for daily hydration tracking.
Scale up bread or pizza dough recipes that specify water in cups.
Teach the difference between US, metric, and imperial cup sizes.
Verify water quantities when mixing powdered drinks or supplements.
Convert tablespoons or teaspoons of water to grams for small-batch recipes.
Check cup-to-ml equivalents when using a non-US measuring cup set.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu