US fluid ounce to Imperial fluid ounce
us fl oz
imp fl oz
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
| No conversion history to show. | ||
Quick Reference Table (US fluid ounce to Imperial fluid ounce)
| US fluid ounce (us fl oz) | Imperial fluid ounce (imp fl oz) |
|---|---|
| 0.5 | 0.52042136539285955665 |
| 1 | 1.0408427307857191133 |
| 1.5 | 1.56126409617857866995 |
| 8 | 8.32674184628575290641 |
| 12 | 12.49011276942862935962 |
| 16 | 16.65348369257150581283 |
| 32 | 33.30696738514301162566 |
About US fluid ounce (us fl oz)
The US fluid ounce (fl oz) is a unit of volume equal to approximately 29.574 milliliters, one sixteenth of a US liquid pint. It is the primary small-volume unit on US food labels, beverage cans, and pharmaceutical liquid measurements. A standard US soda can is 12 fl oz; a coffee shop "tall" is 12 fl oz; a standard shot is 1.5 fl oz. The US fluid ounce is distinct from the imperial fluid ounce (28.413 mL) and should not be confused with the ounce as a unit of mass.
A US soda can is 12 fl oz (355 mL). A US shot glass holds 1.5 fl oz (44 mL). A US water bottle is commonly 16.9 fl oz (500 mL).
About Imperial fluid ounce (imp fl oz)
The imperial fluid ounce (imp fl oz) is a unit of volume equal to one twentieth of an imperial pint, approximately 28.413 milliliters. It is used in the United Kingdom and Commonwealth countries, though metric units have replaced it in most commercial contexts. The imperial fluid ounce is slightly smaller than the US fluid ounce (29.574 mL). UK spirits measures are now defined by law in 25 mL and 35 mL metric measures, which do not align exactly with the imperial fluid ounce.
A single spirits measure in a UK bar is 25 mL or 35 mL — close to, but not exactly, one imperial fluid ounce (28.41 mL).
US fluid ounce – Frequently Asked Questions
What is the difference between a fluid ounce and an ounce?
A fluid ounce (fl oz) is a unit of volume; an ounce (oz) is a unit of mass/weight. One US fluid ounce of water happens to weigh approximately 1.04 avoirdupois ounces — close but not equal. For other liquids, the mass per fl oz varies with density.
How many fluid ounces are in a US cup?
There are exactly 8 US fluid ounces in one US cup (240 mL). A pint is 16 fl oz, a quart is 32 fl oz, and a gallon is 128 fl oz.
What is the difference between US and imperial fluid ounces?
A US fluid ounce is approximately 29.574 mL; an imperial (UK) fluid ounce is approximately 28.413 mL — about 4% smaller. A US pint (16 fl oz) is 473 mL while a UK pint (20 fl oz) is 568 mL, a 20% difference that significantly affects beverage serving sizes.
How many fluid ounces are in a standard water bottle?
The most common US bottled water size is 16.9 fl oz (500 mL). Other sizes include 8 fl oz (237 mL), 20 fl oz (591 mL), and 33.8 fl oz (1 liter).
How many fl oz are in a standard US wine pour?
A standard US restaurant wine pour is 5 fl oz (148 mL). A 750 mL wine bottle yields approximately 5 pours of 5 fl oz each.
Imperial fluid ounce – Frequently Asked Questions
Why did the UK abandon the fluid ounce for spirits but keep the pint for beer?
When the UK metricated in the 1990s, spirits measures were switched to 25 mL and 35 mL because publicans needed precise, legally enforceable pour sizes — and optic dispensers were easy to replace with metric ones. Beer, however, had enormous cultural resistance: the "pint" is deeply embedded in British pub identity, and the Campaign for Real Ale lobbied hard. Parliament granted an explicit exemption allowing draft beer and cider to be sold by the imperial pint. Milk got a similar exemption. The result is a hybrid system where your gin is metric but your beer is imperial.
How many imperial fluid ounces are in a UK pint?
There are exactly 20 imperial fluid ounces in one UK pint (568 mL). In the US system, 1 pint = 16 US fluid ounces (473 mL).
Is the imperial fluid ounce still used?
The imperial fluid ounce is rarely used for commercial transactions in the UK today, which metricated in the 1990s. UK spirits servings are now legally defined in metric (25 mL or 35 mL).
Why is a UK shot 25 mL not one fluid ounce?
When the UK metricated bar measures, the 25 mL "metric measure" replaced older imperial measures. One imperial fl oz (28.41 mL) was not adopted because the EU standardized on 25 mL. So UK shots are not exactly one fl oz.
How many milliliters are in an imperial fluid ounce?
One imperial fluid ounce equals approximately 28.413 mL. One US fluid ounce equals approximately 29.574 mL. Both round to roughly "30 mL" in casual usage, but the precise difference matters in pharmacology.