How this calculator works
These are US customary units, defined exactly through the US gallon: 1 gallon is exactly 3.785411784 L and splits into 128 fluid ounces, so 1 US fluid ounce is exactly 29.5735295625 mL and the customary cup of 8 fluid ounces is exactly 236.5882365 mL. Imperial (UK) measures differ, with an imperial fluid ounce of about 28.4130625 mL, and are out of scope here.
Formula
result = value × F(from) ÷ F(to), where F is the exact millilitres per unit: 1 US fl oz = 29.5735295625 mL; 1 US customary cup = 8 US fl oz = 236.5882365 mL; 1 L = 1000 mL.
Worked example
500 mL to US fluid ounces: 500 ÷ 29.5735295625 = 16.907 fl oz. 8 US fl oz to millilitres: 8 × 29.5735295625 = 236.5882365 mL.
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Frequently asked questions
Are these US or imperial fluid ounces?
US. An imperial fluid ounce is about 28.4130625 mL, roughly 4 percent smaller, so mixing the two systems shifts drink and recipe amounts noticeably.
Is a cup always 236.5882365 mL?
That is the US customary cup. US nutrition labels use a legal cup of exactly 240 mL instead, and the millilitres to cups page converts with both.
Can I convert litres?
Yes. Litres are one of the available units, so enter the volume and choose litres; one litre is 1000 mL.