US Fluid Ounce vs. Imperial (UK) Fluid Ounce to Milliliters (ml) Comparison
This chart clarifies the subtle but important difference between the US fluid ounce (fl oz) and the Imperial (UK) fluid ounce, showing their volumes in metric milliliters (ml).
Unit
Milliliters (ml) (approx.)
Relationship to Pint
1 US Fluid Ounce (fl oz)
29.5735 ml
1/16 of a US Pint
1 Imperial (UK) Fluid Ounce (fl oz)
28.413 ml
1/20 of an Imperial Pint
Difference (US - Imperial)
1.1605 ml
A US fl oz is about 4% larger than an Imperial fl oz.
8 US Fluid Ounces (1 US Cup)
236.59 ml
8 Imperial Fluid Ounces
227.30 ml
(Not typically a "cup" measure in UK)
16 US Fluid Ounces (1 US Pint)
473.18 ml
20 Imperial Fluid Ounces (1 Imperial Pint)
568.26 ml
Key Points:
A **US fluid ounce** is approximately 29.57 ml.
An **Imperial (UK) fluid ounce** is approximately 28.41 ml.
Interestingly, while the Imperial pint and gallon are *larger* than their US counterparts, the Imperial fluid ounce is slightly *smaller* than the US fluid ounce. This is because an Imperial pint contains 20 Imperial fluid ounces, while a US pint contains only 16 US fluid ounces.
This difference can accumulate in recipes using many fluid ounces.
Always verify the origin of a recipe if precise liquid measurements are critical.