Fluid Ounces to Millilitres
Convert US or Imperial fluid ounces to millilitres and litres instantly.
How to use this tool
- Enter fluid ounces and fluid ounce type in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your millilitres and the full breakdown beneath it.
Formula
US fluid ounce: mL = fl oz × 29.5735296
Imperial fluid ounce: mL = fl oz × 28.4130625
Litres = mL ÷ 1000
US cups (US fl oz input) = fl oz ÷ 8
US tablespoons (US fl oz input) = fl oz × 2
How it works
The US fluid ounce (29.5735 mL) and the Imperial fluid ounce (28.4131 mL) are distinct units with different definitions. The US ounce derives from the US gallon (231 cubic inches), while the Imperial ounce derives from the Imperial gallon (277.42 cubic inches). The converter selects the correct factor based on the user's chosen system and derives litres, cups, and tablespoons from the millilitre result.
A common mistake is assuming all fluid ounces are the same — a recipe from the United Kingdom quoting fluid ounces uses the Imperial measure, which is about 4% larger than the US equivalent. Using the wrong type when scaling a recipe can noticeably affect results, especially for liquids like stock or milk in larger quantities.
Worked example
Convert 8 US fluid ounces to mL, litres, cups, and tablespoons
- Select US fluid ounce system (1 US fl oz = 29.5735296 mL).
- Millilitres: 8 × 29.5735296 = 236.588 mL.
- Litres: 236.588 ÷ 1000 = 0.23659 L.
- Cups: 8 ÷ 8 = 1 cup. Tablespoons: 8 × 2 = 16 tbsp.
8 US fl oz = 236.588 mL, 0.23659 L, 1 cup, and 16 tablespoons.
Common mistakes to avoid
- Using the US conversion (29.57 mL/fl oz) for an Imperial (UK) recipe -- a UK fluid ounce is 28.41 mL, so 10 fl oz converts to 284 mL, not 296 mL; the difference matters in custards and sauces.
- Confusing fluid ounces with weight ounces -- "8 fl oz of water" is approximately 8 oz by weight, but "8 fl oz of honey" is about 12 oz by weight; they are only equal for water.
- Rounding to full millilitres too early in a multi-step recipe -- intermediate rounding errors compound when several ingredients are each off by 1-2 mL.
Key terms
- US fluid ounce
- A US liquid volume unit equal to 1/8 of a US cup, 2 tablespoons, or approximately 29.574 mL.
- Imperial fluid ounce
- A British liquid volume unit equal to approximately 28.413 mL — roughly 4% smaller in volume than the US fluid ounce despite sharing the same name.
- Millilitre (mL)
- The standard metric unit for small liquid volumes, equal to one cubic centimetre (cm³) and 1/1000 of a litre.
- US cup
- A US cooking volume equal to 8 US fluid ounces or approximately 236.6 mL. Not to be confused with metric cups (250 mL) used in Australia and Canada.
Frequently asked questions
- How many ml in a fluid ounce?
- 1 US fluid ounce = 29.574 mL. 1 Imperial fluid ounce = 28.413 mL.
- How many fluid ounces in a cup?
- 1 US cup = 8 US fluid ounces.