Fluid Ounce to Millilitre Converter

One UK imperial fluid ounce equals exactly 28.4130625 millilitres. For practical purposes, this is typically rounded to 28.41 ml. This measurement is based on the imperial gallon, where 160 fluid ounces equal one imperial gallon (4.54609 litres).

One US fluid ounce equals exactly 29.5735295625 millilitres, commonly rounded to 29.57 ml. The US fluid ounce is defined as 1/128 of a US gallon (3.785 litres), making it approximately 4% larger than the UK imperial fluid ounce.

The difference stems from historical definitions of the gallon. The UK imperial system bases its measurements on the volume of 10 pounds of water at a specific temperature, whilst the US system retained an older British wine gallon standard. When the UK reformed its measurements in 1824, the US maintained its existing system, creating the divergence that persists today.

For UK imperial: 8 fl oz × 28.4131 = 227.30 ml. For US customary: 8 fl oz × 29.5735 = 236.59 ml. The difference of approximately 9 ml represents the cumulative variance between the two measurement systems across 8 fluid ounces.

100 ml equals approximately 3.52 UK fl oz or 3.38 US fl oz. Therefore, 100 ml is closer to 3.5 fluid ounces than either 3 or 4. This makes it slightly more than three fluid ounces but less than four in both measurement systems.

16 UK imperial fl oz equals 454.61 ml (approximately 0.45 litres), whilst 16 US fl oz equals 473.18 ml. The 16 US fl oz measurement represents one US pint, a common beverage size in the United States.

500 ml equals approximately 17.60 UK imperial fl oz or 16.91 US fl oz. This represents a common bottle size for water, soft drinks, and other beverages in regions that use metric measurements.

UK imperial fluid ounces are traditionally used in the United Kingdom, though metric measurements now dominate. Some Commonwealth nations historically used imperial measurements. US fluid ounces remain prevalent in the United States. Most other countries worldwide primarily use metric units (millilitres and litres) for liquid measurements.

No. Fluid ounces measure volume whilst weight ounces (or simply “ounces”) measure mass. One fluid ounce of water weighs approximately one ounce, but this relationship changes with different liquids based on their density. Honey, for example, is denser than water, so one fluid ounce of honey weighs more than one ounce.

For most cooking purposes, rounding to the nearest 5-10 ml is sufficient. Baking requires more precision, so rounding to 1 ml is advisable. Professional contexts or scientific work may require full precision. Always ensure you’re using the correct measurement system (UK or US) that matches your recipe’s origin.

1 litre (1000 ml) equals approximately 35.19 UK imperial fl oz or 33.81 US fl oz. This difference of about 1.4 fluid ounces reflects the cumulative variance between the two systems across a full litre volume.

For quick mental conversions, remember that 1 UK fl oz is roughly 28 ml and 1 US fl oz is roughly 30 ml. Multiply your fluid ounce value by these approximations. For example, 5 UK fl oz ≈ 5 × 28 = 140 ml (actual: 142.07 ml). This method provides estimates suitable for everyday situations.