Fluid Ounces to Milliliters Converter

"Oz" means two different things. On a drink bottle or a measuring jug it is a fluid ounce, a volume. On a bag of flour or a kitchen scale it is a weight ounce. This page converts the fluid ounce: the US fluid ounce of 29.5735 ml.

The two only line up for water and similar liquids. A US fluid ounce of water weighs about 29.57 g, which is 1.0432 weight ounces, close enough that people treat them as the same. For flour, sugar, honey or oil they drift apart, because an ounce of a dense ingredient takes up less room than an ounce of a light one. If your recipe lists an ingredient by weight, use the ounces-to-grams converter instead.

Two of these are metric sizes in disguise. A 16.9 oz bottle is a 500 ml bottle and a 33.8 oz bottle is a liter; the label rounds the ounces, so the conversion back lands a fraction short.

A UK (imperial) fluid ounce is about 28.4131 ml, 3.92% less than the US one this tool uses. For a single ounce the difference is about a milliliter. It grows with the amount: 20 US fl oz is 591.47 ml, while 20 UK fl oz is about 568.26 ml.

If a recipe or label comes from the UK, convert with 28.4131 ml per ounce, or take this tool's answer and multiply by 0.9608.

• Multiply by 30. The usual shortcut, 1.44% high. A 12 oz can becomes 360 ml against 354.88.
• Multiply by 29.5. Only 0.25% low, and easy enough with a phone calculator.

The result box shows 4 decimals below 100 ml and 2 decimals from 100 ml up, so 8 fl oz reads 236.59. For a drink, round to the nearest 5 or 10 ml. Keep the decimals only if you are scaling a formula or a batch where small errors multiply.