1 cup = 236.5882365 mL. Milliliters are shown to three decimal places. The exact factors are in the notes below.
How it works
A cup in a recipe is not one milliliter value. American cookbooks, US nutrition labels, metric recipes, and Australian spoons each freeze a different size, and this page will not guess which one you meant. Choose the definition that matches the source you are cooking from, type any one of milliliters, cups, tablespoons, teaspoons, or US fluid ounces, and the other fields follow. The step is a multiply or a divide. Flour, sugar, and butter are not converted to grams here, because those depend on how the ingredient sits in the cup.
Every amount is turned into milliliters, then back out. The US customary column uses the international inch, 0.0254 m exactly, and the US gallon of 231 cubic inches. That gallon is 3.785411784 liters, so one US fluid ounce is 29.5735295625 mL. A customary cup is eight of those ounces: 236.5882365 mL. A tablespoon is half an ounce, 14.78676478125 mL, and a teaspoon is one third of a tablespoon, 4.92892159375 mL. Sixteen tablespoons, or 48 teaspoons, fill one customary cup. The milliliter field rounds to three decimal places, so 1 customary cup is shown as 236.588 mL. The factor above is the one the page multiplies.
Four definitions, not one slider
The US legal column is the household set used on American nutrition labels: 1 cup = 240 mL, 1 tablespoon = 15 mL, 1 teaspoon = 5 mL, and 1 fluid ounce = 30 mL. Eight of those ounces land on 240 mL, so the legal cup and the legal ounce agree with each other. They do not agree with the customary cup. One legal cup is 3.4117635 mL larger. You will not taste that in a single cup of stock. In a batch of eight cups the gap is about 27 mL, a little under two tablespoons.
The metric column uses a 250 mL cup, a 15 mL tablespoon, and a 5 mL teaspoon. The fluid-ounce field stays at 30 mL so the row still shows a US labeling ounce. A 250 mL cup is 8.333 of those ounces, not 8. The Australian column keeps the 250 mL cup and the 5 mL teaspoon, but the tablespoon is 20 mL. An Australian cup is 12.5 tablespoons, not 16. A Melbourne recipe that says “1 tablespoon” is 5 mL short if you scoop it with a US spoon.
Volume is not weight
A cup of all-purpose flour is often near 120 g when it is spooned and leveled, and a cup of granulated sugar is often near 200 g. Those are densities for particular ingredients, not identities of the cup. This page never applies them. A Japanese cup of 200 mL, a stick of butter, and the old British cup of 10 imperial fluid ounces are not in the selector. If the author is in the United States and does not name a milliliter value, older cookbooks usually mean the customary cup, while a label or a site that writes “1 cup = 240 mL” means the legal cup.
Worked examples
Input: US customary, 1 cup
Output: 236.588 mL on screen (exact 236.5882365 mL), 8 fl oz, 16 tbsp, 48 tsp
Input: US legal, 1 cup, or 16 tablespoons
Output: 240 mL. One tablespoon is 15 mL and one teaspoon is 5 mL
Input: Australian, 1 tablespoon, and 1 cup
Output: 20 mL for the spoon. The cup is 250 mL, which is 12.5 Australian tablespoons
Limits
- Milliliters are shown to three decimal places. The customary teaspoon’s exact value is 4.92892159375 mL and the field shows 4.929.
- Switching definition reinterprets the field you last typed. A typed “1” in the cup box becomes 240 mL or 250 mL when you leave US customary. The milliliter box does not jump, because its factor is 1 in every column.
- There is no imperial fluid ounce (28.4130625 mL) and no conversion from volume to grams.
Common mistakes
- Treating every “cup” on the internet as 250 mL. A US customary cup is 236.5882365 mL, and a US nutrition-label cup is 240 mL.
- Using a 15 mL spoon for an Australian tablespoon. The gap is 5 mL, and three spoons in a sauce is 15 mL.
- Counting 16 tablespoons in a 250 mL metric cup. At 15 mL each, that cup is 16 tablespoons plus 10 mL, not a clean 16.
Questions
Why does 1 cup not show 240?▾
Are the tablespoon and the fluid ounce in the metric column American?▾
Can I convert 2/3 cup?▾
Sources
- US gallon: 231 cubic inches. International inch: 0.0254 m exactly. One US gallon is therefore 3.785411784 L.
- US nutrition-label household measures: 1 cup = 240 mL, 1 tablespoon = 15 mL, 1 teaspoon = 5 mL, 1 fluid ounce = 30 mL (21 CFR 101.9).
- Australian metric cooking: 1 cup = 250 mL and 1 tablespoon = 20 mL. A teaspoon remains 5 mL.