Oz to mL Converter — Fluid Ounces to Millilitres
Convert between fluid ounces and millilitres in both directions. Choose US fluid ounces (29.574 mL) or UK/Imperial fluid ounces (28.413 mL) — the two differ by about 4%, which matters for precise recipes and medication doses.
Fluid ounce type
fl oz
mL
Exact conversion at the selected oz standard
- 1
Conversion factor
1 fl oz = 29.5735 mL = 29.5735 - 2
Millilitres
8 × 29.5735 = 236.59
How does this calculator work?
mL = fl oz × 29.5735 for US fluid ounces, or × 28.4131 for UK/Imperial ounces. 8 US fl oz = 236.6 mL (one US cup); 8 UK fl oz = 227.3 mL. Enter ounces or mL and pick the oz standard to convert instantly in either direction.
Formula
How this is calculated
The fluid ounce is a unit of volume used in the US and UK, but the two are not the same size. The US fluid ounce is defined as exactly 29.5735295625 mL (1/128 of a US gallon). The UK/Imperial fluid ounce is defined as exactly 28.4130625 mL (1/160 of an Imperial gallon). The difference is about 4%: 8 US fl oz = 236.6 mL, while 8 UK fl oz = 227.3 mL.
For cooking and everyday use the difference is usually small enough to ignore. For pharmaceutical dosing, scientific measurements, and commercial beverage labelling it can matter — US and UK liquid product labels use different oz volumes. Whenever a recipe or label specifies "fl oz" without qualification, check whether it is a US or UK source.
This converter works in both directions: enter ounces to get mL, or enter mL to get ounces. The conversion factor is exact (by definition), so rounding only occurs in the display.
Frequently asked questions
No. A fluid ounce is a unit of volume; a (weight) ounce is a unit of mass. For water at 4 °C they are approximately equal (1 US fl oz ≈ 1.04 oz of water) but for other liquids they differ significantly — do not interchange the two.
Exactly 29.5735295625 mL, or roughly 29.57 mL. For quick estimation, 1 US fl oz ≈ 30 mL.
8 US fl oz = 236.59 mL (one US cup). 8 UK fl oz = 227.30 mL. Always check whether the recipe uses US or UK measurements.
Also known as
TG we-Calculate Editorial Team. (2026). Oz to mL Converter — Fluid Ounces to Millilitres [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/oz-ml-converter
TG we-Calculate Editorial Team. "Oz to mL Converter — Fluid Ounces to Millilitres." TG we-Calculate. 2026. https://we-calculate.com/calculator/oz-ml-converter.
TG we-Calculate Editorial Team, "Oz to mL Converter — Fluid Ounces to Millilitres," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/oz-ml-converter
@misc{wecalculate_oz_ml_converter, title = {Oz to mL Converter — Fluid Ounces to Millilitres}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/oz-ml-converter}}, year = {2026}, note = {TG we-Calculate} }
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