Oz to mL converter, US fluid ounces to milliliters.

To convert fluid ounces to mL, multiply the ounces by 29.5735. One US fluid ounce is 29.5735 mL, 8 fl oz is 236.59 mL and 16 fl oz is 473.18 mL. This page reads "oz" as a fluid ounce, the unit of volume used for drinks. The ounce on a kitchen scale is a unit of weight and has no fixed number of mL, as the mistakes section explains.

How to use the converter

1. Type the amount in the US fluid ounces (fl oz) box, for example 12.
2. The big result shows mL. The cards show the same volume in US cups, tablespoons and UK fluid ounces.
3. Type mL in the second box to go back, or open the ML to oz converter page.
4. Use Decimals to round: 0 for a drink, 1 or 2 for a dose of liquid. Auto shows up to five places.
5. Press Copy result, Copy link or Print chart. Click a row in Common values to load it.

The definition

The US gallon is defined as 231 cubic inches, and NIST Handbook 44 (2026), Appendix C lists it as 128 US fluid ounces exactly. Page checked 18 Oct 2026. With 2.54 cm to the inch, 231 cubic inches is 3,785.411784 mL, and a 128th of that is 29.5735295625 mL. The number ends, so the factor is exact. NIST rounds it to 29.573 mL in the same appendix.

The British fluid ounce is different. The same appendix gives the British gallon as 4.546 liters, divided into 160 fluid ounces, so a British ounce is about 28.41 mL, a little less. The card under the result uses the more exact 4.54609 liters and shows 28.413 mL per UK ounce.

A shortcut and its error

Multiply by 30. Food labels do this: 21 CFR 101.9(b)(5)(viii) says that, for nutrition labelling, 1 fl oz means 30 mL. For 12 fl oz that is 360 mL, and the exact answer is 354.88 mL, so the shortcut is 5.12 mL high. That is 1.44 percent high on any amount. For 128 fl oz, a US gallon, the shortcut says 3,840 mL against 3,785.4, a gap of about 55 mL. A closer rule: multiply by 30 and take off one part in seventy.

Worked examples

• A cup, 8 fl oz. 8 × 29.5735295625 = 236.588 mL. The label rule would say 240 mL.
• A 12 fl oz can. 12 × 29.5735295625 = 354.88 mL.
• A 20 fl oz bottle. 591.5 mL, which is 2.5 cups.
• A 1.5 fl oz shot. 44.36 mL, or 3 tablespoons.
• 3.4 fl oz. 100.55 mL, which is just over 100 mL. The carry-on liquid limit is written as 3.4 ounces and 100 milliliters on the TSA liquids rule. The two figures are not exactly equal, so go by the number printed on the container and read that page for the rule.

US ounce, UK ounce and the label ounce

The same number of ounces gives three different volumes. The table shows the US fluid ounce, the UK fluid ounce and the 30 mL used on US labels.

A UK pint is 20 UK fluid ounces and a US pint is 16 US ounces, so the UK pint is 568.3 mL and the US pint is 473.2 mL. Drinks, recipes and medicine labels from the UK can use the UK ounce, so check where a figure comes from before you convert.

Mistakes that are specific to oz and mL

The biggest is weight against volume. 8 oz on a food scale is a weight, about 226.8 g. 8 fl oz is a volume, 236.6 mL. They are not the same thing, and the gap depends on the liquid. No converter can turn one into the other without knowing the density. For weight, see the Ounces to grams. The second mistake is the UK ounce, shown above. The third is a label that reads "oz" for a liquid: it usually means a fluid ounce, and a number in brackets in mL is usually the rounded 30 mL rule.

Check the answer by going back

Divide the mL by 29.5735295625 and you should have the ounces you started with. For 12 fl oz: 354.882 mL ÷ 29.5735295625 = 12 fl oz. Milliliters are always the bigger number, about thirty times the ounces.

Common drink sizes from the other side

Many packs are sold in milliliters, and the question is how many ounces that is. The exact US fluid ounces for some common sizes are below.

The sizes do not match round ounces, so 500 mL is not 16 fl oz: it is 16.91. For a full table see the ML to oz converter.

Who uses oz to mL

Travellers who buy a drink or toiletries in the US and read a bottle in mL. Parents measuring a baby bottle or medicine in fluid ounces. Bartenders working from a recipe in ounces who pour by the milliliter. Cooks reading an American recipe. For the opposite direction, use the ML to oz converter. For cups, see Ounces to cups converter.