1 Cup of Water in Grams: The Short Answer
One US cup of water weighs 236 grams (236.6 g at room temperature, 236.1 g at 20 °C). One metric cup of water weighs 250 grams. One US legal cup — the one nutrition labels use — holds 240 grams.
Water is the easiest ingredient in the kitchen to convert, because the conversion is not approximate. It is a definition.
| Cup standard | Volume | Water weight |
|---|---|---|
| US customary cup | 236.6 mL | 236 g |
| US legal cup (nutrition labels) | 240 mL | 240 g |
| Metric cup (AU / CA / NZ) | 250 mL | 250 g |
| UK imperial cup (legacy) | 284.1 mL | 284 g |
| ½ US cup | 118.3 mL | 118 g |
| ⅓ US cup | 78.9 mL | 79 g |
| ¼ US cup | 59.1 mL | 59 g |
| 1 US tablespoon | 14.79 mL | 14.8 g |
| 1 US teaspoon | 4.93 mL | 4.9 g |
If you take one number away, take this one: 236 g per US cup. Skip the arithmetic entirely with our Kitchen Measurement Converter, which handles water, milk, oil, and 40+ other ingredients in both directions.
Why 1 mL of Water Is (Almost Exactly) 1 Gram
The metric system was built on water. The original definition of the gram was “the mass of one cubic centimeter of pure water at 4 °C,” and it is still good to within about 0.002% today. That means for water, milliliters and grams are the same number — no density lookup required.
This is why water is the one ingredient where a liquid measuring cup doubles as a scale. Set the cup down, fill to the 236 mL line, and you have 236 g.
The tiny caveat is temperature. Water’s density peaks at 4 °C (39 °F) and falls off slowly as it warms:
| Water temperature | Density (g/mL) | 1 US cup (236.6 mL) weighs |
|---|---|---|
| 4 °C (39 °F) | 1.0000 | 236.6 g |
| 20 °C (68 °F) | 0.9982 | 236.2 g |
| 40 °C (104 °F) | 0.9922 | 234.8 g |
| 60 °C (140 °F) | 0.9832 | 232.6 g |
| 100 °C (212 °F, boiling) | 0.9584 | 226.8 g |
A cup of boiling water weighs about 10 g less than a cup of cold water. For recipe purposes, ignore it — a 4% difference in water is far below the noise level of most baking. Where it does matter is when you are measuring hot water by weight and then comparing it against a volume target, such as calibrating a coffee brewing ratio at 200 °F.
Water in Recipes: Where the Gram Number Actually Gets Used
Water shows up less as “add 1 cup of water” and more as a hidden ratio, and those are the cases where you want the gram figure.
Bread and pizza dough. Hydration is expressed as a percentage of flour weight, not a cup count. A 70% hydration dough with 500 g of flour needs 350 g of water — which is 1.48 cups, not a round 1½ cups. Estimating “about 1½ cups” gives you 355 g, a 1.4% hydration error, which is genuinely fine. Estimating “about 1 cup” gives you 236 g and a 47% hydration dough that will not come together. Run the numbers with the Dough Hydration Calculator rather than guessing.
Brines and salt solutions. A 5% brine is 5 g of salt per 95 g of water — by weight, because salt’s volume varies wildly between kosher, table, and flake. 1 cup of water (236 g) plus 12.4 g of salt gives you roughly a 5% solution. Weigh the salt, measure the water, and use the Brine Calculator to scale to the size of your bird or pork loin.
Simple syrup and sugar solutions. A 1:1 simple syrup by volume is 1 cup of water to 1 cup of sugar. By weight it is 236 g of water to 200 g of sugar — not 1:1 at all. Syrup made by the volume method comes out slightly richer, and cocktail recipes written by weight will not match. Use the Sugar & Salt Calculator if you want the two methods to line up.
Rice and grains. Most rice cooks at roughly 2:1 water to rice by volume, which is about 236 g of water per 185 g of dry rice. Doubling a batch means doubling both, and the pot size becomes the limiting factor long before the ratio does.
Gelatin and starches. Blooming gelatin calls for cold water in a specific multiple of the gelatin’s weight — commonly 5 parts water to 1 part gelatin. 10 g of gelatin needs 50 g of water, which is 3.4 tablespoons, not a quarter cup (59 g, an 18% overshoot).
Measuring 236 Grams of Water Without a Scale
Since the density is 1, the conversion is trivial:
- 1 US cup = 236 g. Fill a liquid measuring cup to the 1-cup / 8 fl oz line.
- ½ US cup = 118 g. The 4 fl oz line.
- 250 g (metric) = 250 mL. The 1-cup line on an Australian or Canadian jug.
- 240 g (US legal cup) = 240 mL. What a US nutrition label means by “1 cup.”
- 1 fl oz = 29.6 g. Useful for small amounts.
- 1 tbsp = 14.8 g; 1 tsp = 4.9 g. For any quantity under a quarter cup.
Read liquid measurements at eye level, with the cup on a flat surface, and check the bottom of the meniscus rather than the top of the curve — that curve is worth about 2–3 mL, or roughly 2 g.
For a full recipe, be consistent: measure the water in the same cup every time. Mixing a dry cup for flour and a liquid cup for water is fine, but mixing a US cup for one ingredient and a metric cup for another is not.
Scaling Water Quantities in a Recipe
Water scales linearly — no tricks, no leavening interactions — but three things around it do not:
- Evaporation. Doubling a simmer time does not double the evaporation; it roughly quadruples the surface area you expose over that time only if you also widen the pot. A doubled stew in the same narrow pot often finishes with more liquid than you expect.
- Pan surface area. If you scale a recipe up, check the pan with the Baking Pan Converter before you commit. A water bath recipe scaled to a larger pan needs its own volume checked too — a 9×13 pan holds about 3 quarts, and the water bath needs to come halfway up the sides.
- Dissolved solids. If the water carries salt or sugar, the solution’s weight is higher than the water alone. 1 cup of 5% brine weighs about 248 g, not 236 g. When you scale a brine, scale the salt and the water separately rather than the finished solution.
If you are scaling servings and want every liquid quantity recalculated together, the Recipe Servings Calculator does the whole ingredient list in one pass.
Quick Reference
- 1 US cup of water = 236 g = 236.6 mL = 8 US fl oz
- 1 metric cup of water = 250 g = 250 mL
- 1 US legal cup of water = 240 g = 240 mL
- 1 tablespoon of water = 14.8 g
- 1 teaspoon of water = 4.9 g
- 1 US pint of water = 473 g (2 cups)
- 1 US quart of water = 946 g (4 cups)
- 1 US gallon of water = 3,785 g (16 cups)
For comparison, the same cup of all-purpose flour weighs only 120 g — water is roughly twice as dense as flour. The printable Conversion Chart puts water, flour, sugar, butter, and oven temperatures on a single page.
Try Our Free Tools
The Kitchen Measurement Converter converts water and 40+ other ingredients between cups, grams, milliliters, and ounces instantly. When water is doing real work in a recipe, use the Dough Hydration Calculator for bread, the Brine Calculator for anything you are soaking, and the Sugar & Salt Calculator for syrups and solutions. Free, no signup, works on your phone.