ML to oz converter, milliliters to US fluid ounces.

To convert mL to oz, divide the milliliters by 29.5735. This converter uses the US fluid ounce, so 100 mL is 3.381 fl oz, 250 mL is 8.454 fl oz and 1 liter is 33.814 fl oz. A fluid ounce measures volume, not weight, so this is not the same as the ounce on a kitchen scale. The UK fluid ounce is a little smaller, and a card on the page gives it too.

How to use the converter

1. Type the volume in the Milliliters (mL) box, for example 250.
2. The big result shows US fluid ounces (fl oz). The cards show US cups, tablespoons, teaspoons and UK fluid ounces for the same amount.
3. Type ounces in the other box to go back to milliliters.
4. Set Decimals to 1 for a drink or 2 for a dose of liquid. Auto shows up to five places.
5. Click a value in Common values to load it, press Copy result to copy it, or Print chart for a sheet.

The definition

The US gallon is defined as exactly 231 cubic inches, and a US fluid ounce is 1/128 of it. NIST Handbook 44 (2026), Appendix C lists "1 gallon (gal) (U.S.) 231 cubic inches (exactly)" and "128 U.S. fluid ounces (exactly)", and gives the fluid ounce as 29.573 milliliters. Working it out from 231 cubic inches at 2.54 cm to the inch, one US fluid ounce is exactly 29.5735295625 mL. NIST Special Publication 811, Appendix B.8 rounds it to 29.57353 mL. Both were checked 18 Oct 2026.

The UK fluid ounce is different. NIST Handbook 44 (2026), Appendix C lists 160 British fluid ounces to the British gallon and says the US ounce is 1.041 British ounces. Using the UK gallon of 4.54609 liters, a UK fluid ounce is about 28.41 mL. So 100 mL is 3.381 US fl oz and 3.52 UK fl oz.

A shortcut and its error

Divide by 30. That is the rule US food labels use. 21 CFR 101.9(b)(5)(viii) says 1 fl oz means 30 mL for nutrition labelling. For 240 mL: 240 ÷ 30 = 8 fl oz. The exact figure is 8.115. Dividing by 30 gives a number 1.42 percent too low, which hides the difference between 29.57 and 30 mL on a large volume: 2,000 mL is 67.63 fl oz exactly and 66.67 by the shortcut.

Worked examples

• A 500 mL bottle. 500 ÷ 29.5735295625 = 16.907 fl oz.
• A 330 mL can. 330 ÷ 29.5735295625 = 11.16 fl oz.
• A 15 mL tablespoon. 15 ÷ 29.5735295625 = 0.5072 fl oz. A US tablespoon is exactly half a fluid ounce, which is 14.7868 mL, so 15 mL is a close, rounded tablespoon.
• A carry-on liquid limit. The TSA liquids rule says containers must be 3.4 ounces (100 milliliters) or less. 100 mL is 3.3814 fl oz, and 3.4 fl oz is 100.55 mL, so both numbers are rounded.
• A 1.5 liter bottle. 1,500 mL is 50.72 fl oz, or 6.34 US cups.

Mistakes that are specific to mL and oz

First, US against UK. The UK pint has 20 fluid ounces and the US pint has 16, and the ounces differ in size, so a UK pint of 20 UK oz is 568.26 mL, which is 19.22 US fluid ounces. Always know which one a drink or recipe uses. Second, weight against volume: an ounce on a scale is mass, so 30 g of honey is not 30 mL. The Grams to ounces converter is for weight. Third, rounded labels. A label that says 8 fl oz (240 mL) uses the 30 mL rule, not the exact one: 240 mL is 8.12 fl oz exactly.

Bottles and cans in US and UK fluid ounces

Drinks are sold in round metric sizes. The table shows each in US and UK fluid ounces, because one is the ounce on a US label and the other the ounce in a UK recipe.

The UK number is always larger, since a UK ounce is smaller. The ratio is 1.0408 UK ounces to a US ounce. NIST Handbook 44 rounds it to 1.041.

Cooking spoons and doses

A US teaspoon is 4.929 mL and a US tablespoon is 14.787 mL, both exact for the US system, while labels use 5 mL and 15 mL. A 5 mL dose from a syringe is 0.1691 fl oz. When a medicine or recipe gives milliliters, follow the milliliters. The ounces are a courtesy. The tool does the sums, and a dose is a question for a pharmacist and not for a converter.

Who uses mL to oz

Travellers packing toiletries for a flight. Parents mixing formula or medicine in a US dosing cup. Cooks and bartenders moving between metric recipes and US jiggers. Shoppers comparing a bottle in mL with one in fl oz. For cups see the Ounces to cups converter.