How to convert mL to fluid ounces
A US fluid ounce equals 29.5735 millilitres, so to convert: fl oz = mL ÷ 29.5735. For example, 250 mL ÷ 29.5735 = about 8.45 fl oz. (The UK/imperial fluid ounce is slightly smaller at 28.4131 mL.)
Worked examples: a 330 mL can is 11.16 fl oz, a 500 mL bottle is 16.91 fl oz, and a 750 mL bottle of wine is 25.36 fl oz. One litre is 33.81 fl oz, which is why US labels show 33.8 fl oz.
The imperial difference adds up quickly: 500 mL is 16.91 US fl oz but 17.6 imperial fl oz, and a UK pint of 568 mL holds 20 imperial fluid ounces against the 16 fl oz (473 mL) of a US pint.
If you are checking your work, the mL to cups calculator gives you a second reference point.
How to use this calculator
Enter the volume in millilitres and read the result in US fluid ounces. To go the other way, use the oz to mL calculator.
Doses and recipes are where this matters most. Medical instructions are almost always metric, so a 5 mL spoon is 0.17 fl oz and a 15 mL tablespoon is 0.51 fl oz. In cooking, rounding to a flat 30 mL per ounce is close enough, since the error is under 1.5%, but keep the full 29.5735 factor for volumes measured in litres.
Airline liquid limits are a good example: the 100 mL cabin rule is 3.38 fl oz, which is why US travel bottles are sold at 3 fl oz, or 88.7 mL, to stay safely inside it.
The cups to mL calculator is the natural next step once you have this figure.
Frequently asked questions
- How many ounces is 250 mL?
- About 8.45 US fluid ounces (250 ÷ 29.5735).
- How do I convert mL to oz?
- Divide the millilitres by 29.5735 for US fluid ounces.
- Is a US and UK fluid ounce the same?
- No. A US fluid ounce is 29.5735 mL; a UK (imperial) fluid ounce is 28.4131 mL.
- How many mL in a fluid ounce?
- 29.5735 mL in one US fluid ounce.
- Is a fluid ounce the same as an ounce of weight?
- No. A fluid ounce measures volume while an ounce measures weight (28.35 g). They almost coincide for water, where one US fluid ounce weighs about 1.04 oz, but for oil or honey the two numbers pull apart.