Water: Cup Standards, Weight & Measuring Guide

The reference liquid whose mass is close to its milliliter volume at ordinary kitchen temperatures.

1 cup = 240g

Water

Measured

poured to the 240 ml line and read at eye level

What is water?

Water is the main solvent in many doughs and batters: it dissolves ingredients, hydrates starch and proteins, and helps wheat proteins form gluten. Its familiar density makes it a useful reference for understanding mass and volume, but it does not make other liquids or dry ingredients interchangeable with water.

This page explicitly defines the default as a 240 ml US cup of fresh water near room temperature. Under that standard the site’s versioned data model gives about 240 grams; another cup standard has a different volume even though the ingredient is unchanged. Read a liquid measuring cup on a level surface at eye level.

Measurement profile

Grams per cup: 240g
Cup standard: US cup / 240 ml
Ingredient state: fresh water, near room temperature
Confidence: High

Data last verified: August 5, 2026

Source observations

U.S. Geological Survey — Water Density1 g/1 ml (approximate) · fresh-water density; temperature dependent
King Arthur Baking — Ingredient Weight Chart227 g/1 source cup (exact volume unknown) · poured liquid

Why measurements vary

Cup standard

A US cup, US customary cup, and metric cup are different volumes, so “one cup” must be defined before assigning a mass.

Temperature and dissolved minerals

Both change water density slightly, although the difference is usually immaterial for ordinary kitchen work.

How to measure water

poured to the 240 ml line and read at eye level

At ordinary kitchen temperatures, fresh water is close to 1 gram per milliliter, so 240 ml is about 240g.
Temperature and dissolved minerals change density slightly; this difference is usually immaterial in home baking.
Use a liquid measuring cup on a level surface and read the bottom of the meniscus at eye level.

Types & varieties

Fresh water near room temperature

240g per cup

Normalized from approximately 1 gram per milliliter to a 240 ml cup.

Very hot, cold, or mineral-rich water

Density changes slightly with temperature and dissolved substances.

Common water measurements

These limited reference values are derived from the canonical cup weight. Use the converter for any other amount.

Cups	Grams
¼ cup	60g
⅓ cup	80g
½ cup	120g
1 cup	240g

Common substitutes

Milk

Mostly water but slightly denser and compositionally different.

Related measurement resources

Convert water grams to cups

Convert cups of water to grams

Browse related ingredient guides

How ingredient measurements are verified

Frequently asked questions

How many grams are in a 240 ml cup of water?

At ordinary kitchen temperatures, 240 ml of fresh water is about 240 grams.

Is water always exactly 1 gram per milliliter?

No. That is a practical approximation; temperature and dissolved minerals cause small density changes.

Why is water a useful kitchen reference?

Its density near ordinary kitchen temperatures makes milliliters and grams numerically close, which is convenient for checking volume and mass. Other ingredients do not inherit that relationship.

What does water do in doughs and batters?

It dissolves salt and sugar, hydrates starch and proteins, and helps gluten develop in wheat dough. The amount still depends on the recipe and flour, not on a universal hydration rule.