What is Imperial fluid ounce?
An Imperial fluid ounce is a volume unit used in the United Kingdom equal to approximately 28.41 millilitres. It is used in British cooking recipes, beverage servings, and pharmaceutical labelling.
Real-world uses
Imperial fluid ounces are used in the United Kingdom, Canada (in some contexts), and other Commonwealth countries for beverage serving sizes and recipe measurements. A British pint is 20 Imperial fluid ounces, compared to the US pint of 16 US fluid ounces.
History
The Imperial fluid ounce was defined by the British Weights and Measures Act of 1824, which established the Imperial gallon based on the volume of 10 pounds of water at 62°F. One Imperial fluid ounce is 1/160 of that gallon.
Common mistakes
Assuming Imperial and US fluid ounces are the same. An Imperial fluid ounce is about 28.41 mL versus 29.57 mL for the US version. This means an Imperial pint (568 mL) is larger than a US pint (473 mL).
What is Imperial gallon?
An Imperial gallon is a volume unit used in the United Kingdom equal to approximately 4.546 litres. It is larger than the US gallon and is commonly referenced for fuel efficiency (miles per gallon) in the UK.
Real-world uses
Imperial gallons are used in the United Kingdom, Canada (for some purposes), and several Caribbean countries. British fuel economy was historically quoted in miles per Imperial gallon. Older Commonwealth-era recipes and industrial specifications may reference Imperial gallons.
History
The Imperial gallon was established by the British Weights and Measures Act of 1824 as the volume occupied by 10 pounds of water at 62°F (≈ 17°C). It replaced several older gallon definitions including the wine gallon (retained by the US) and the ale gallon.
Common mistakes
Assuming the Imperial gallon equals the US gallon. The Imperial gallon is about 4.546 litres versus 3.785 litres for the US gallon. Converting mpg figures between the two systems without adjusting for gallon size gives misleading results.
When is this conversion used?
Converting Imperial fluid ounce to Imperial gallon is useful in the volume domain when comparing values across different measurement standards or applying formulas that require a specific unit.
Worked examples
1 Imperial fluid ounce = 0.00625 Imperial gallon
1 Imperial gallon = 4.54609 litre
How to convert Imperial fluid ounce to Imperial gallon
To convert Imperial fluid ounce to Imperial gallon, multiply the value by 0.00625.
To convert Imperial gallon back to Imperial fluid ounce, multiply by 160.
Measurement standards
The cubic metre is the SI derived unit of volume. The litre, equal to exactly one cubic decimetre (0.001 m³), is accepted by the BIPM for use alongside SI units. Both the lowercase "l" and uppercase "L" are approved symbols for the litre.
Did you know?
An Olympic swimming pool holds 2,500 cubic metres of water — about 2.5 million litres. The Amazon River discharges roughly 209,000 cubic metres per second, enough to fill 84 Olympic pools every single second.
Quick reference: Imperial fluid ounce to Imperial gallon
| Imperial fluid ounce | Imperial gallon |
|---|---|
| 0.1 | 0.000625 |
| 0.5 | 0.003125 |
| 1 | 0.00625 |
| 2 | 0.0125 |
| 5 | 0.03125 |
| 10 | 0.0625 |
| 25 | 0.15625 |
| 50 | 0.3125 |
| 100 | 0.625 |
| 250 | 1.5625 |
| 500 | 3.125 |
| 1,000 | 6.25 |
Common values
| Imperial fluid ounce | Imperial gallon | |
|---|---|---|
| A teaspoon | 0.1759754 Imperial fluid ounce | 0.00109985 Imperial gallon |
| A cup of coffee | 8.79876993 Imperial fluid ounce | 0.05499231 Imperial gallon |
| A water bottle | 17.59753986 Imperial fluid ounce | 0.10998462 Imperial gallon |
| A bathtub | 10,558.52391836 Imperial fluid ounce | 65.99077449 Imperial gallon |
| A swimming pool (Olympic) | 87,987,699.31963512 Imperial fluid ounce | 549,923.12074772 Imperial gallon |
Available Volume units
More Imperial fluid ounce conversions
- Convert Imperial fluid ounce to litre
- Convert Imperial fluid ounce to millilitre
- Convert Imperial fluid ounce to US gallon
- Convert Imperial fluid ounce to cubic metre
- Convert Imperial fluid ounce to Imperial gallon
- Convert Imperial fluid ounce to US fluid ounce
- Convert Imperial fluid ounce to teaspoon (metric)
- Convert Imperial fluid ounce to tablespoon (metric)
- Convert Imperial fluid ounce to cubic centimetre