oz to mL Converter
Enter fluid ounces and get milliliters using the exact definition 1 US fl oz = 29.5735295625 mL. A reverse row also converts the same number the other way (mL → oz).
Example: with Fluid ounces (fl oz) 8 · Ounce definition US fluid ounce (29.5735 mL) → Milliliters: 236.59 mL.
Computed by the calculator below using its default values. Change any input to see your own numbers.
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Check it outHow many mL in an ounce?
One US fluid ounce is exactly 29.5735295625 mL, so to convert ounces to ml you multiply by 29.5735. An 8 fl oz cup of water is 236.59 mL, a 12 fl oz can is 354.88 mL, and a 16.9 fl oz bottle is 499.79 mL — which is why those bottles are sold as “500 mL.”
Watch the wording on “1 ounce to ml” questions. A fluid ounce is volume, so 1 fl oz of any liquid — water, oil, or syrup — is 29.57 mL. A weight ounce (28.35 g) is different: one weight-ounce of water occupies only about 28.35 mL, and other liquids differ with density. UK recipes differ too: the imperial fluid ounce is 28.4131 mL, which is how a 20 fl oz imperial pint lands at 568 mL while a 16 fl oz US pint is 473 mL.
How it’s calculated
Milliliters = fluid ounces × 29.5735295625, the exact NIST definition of the US fluid ounce (1/128 of a 231 cubic-inch gallon). The dropdown swaps in 30 mL for the FDA nutrition-label ounce or 28.4130625 mL for the UK imperial fluid ounce. Liters divide the result by 1,000; the reverse row divides your number by the same factor to go mL → oz.
Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.
Common mistakes
- Converting weight ounces with a volume factor — 1 oz of honey on a scale is not 29.57 mL.
- Ignoring the UK imperial ounce (28.41 mL): a British 10 fl oz recipe cup is 284 mL, not 296 mL.
- Rounding to 30 mL per oz in medicine or baking — that shortcut adds about 1.4% every time.
Frequently asked questions
How many ml are in an oz?
1 US fluid ounce = 29.5735 mL exactly. The UK imperial fluid ounce is slightly smaller in volume terms at 28.4131 mL.
How many ml is 8 oz?
8 × 29.5735 = 236.59 mL — one standard US cup. Sixteen ounces (a US pint) is 473.18 mL.
How many ml is 1 ounce of water?
As a fluid ounce, 29.57 mL for any liquid, water included. As a weight ounce, 1 oz of water (28.35 g) fills about 28.35 mL because water's density is 1 g/mL.
How many ounces are in 500 ml?
500 ÷ 29.5735 = 16.91 US fl oz. That's the reverse direction — divide instead of multiply.
Is 1 fl oz 30 ml?
Only on nutrition labels, where the FDA defines the ounce as 30 mL for round numbers. The customary US fluid ounce is 29.5735 mL.