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 litre?
The litre is a metric unit of volume equal to one cubic decimetre. It is widely used for measuring liquid quantities in cooking, beverages, fuel, and laboratory work across metric countries.
Real-world uses
Litres are the global standard for beverage volumes, fuel tank capacities, engine displacement, and liquid medications. Water intake recommendations are given in litres (about 2 L/day), and swimming pools are measured in thousands of litres.
History
The litre was originally defined in 1795 as one cubic decimetre. In 1901 it was redefined based on the mass of water, creating a tiny discrepancy with the cubic decimetre. In 1964, the original definition (1 L = 1 dm³ exactly) was restored.
Common mistakes
Confusing litres with liters (both are correct—"litre" is the international spelling, "liter" is American). Also, assuming 1 litre of any liquid weighs 1 kg; this is only true for water at 4°C.
When is this conversion used?
Converting between Imperial fluid ounce and litre is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. Fuel economy, beverage volumes, and liquid measurements frequently require converting between litres and US gallons, especially for automotive and cooking contexts across different markets.
Worked examples
1 Imperial fluid ounce = 0.02841306 litre
1 litre = 1 litre
How to convert Imperial fluid ounce to litre
To convert Imperial fluid ounce to litre, multiply the value by 0.02841306.
To convert litre back to Imperial fluid ounce, multiply by 35.19507973.
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 litre
| Imperial fluid ounce | litre |
|---|---|
| 0.1 | 0.00284131 |
| 0.5 | 0.01420653 |
| 1 | 0.02841306 |
| 2 | 0.05682612 |
| 5 | 0.14206531 |
| 10 | 0.28413062 |
| 25 | 0.71032656 |
| 50 | 1.42065312 |
| 100 | 2.84130625 |
| 250 | 7.10326562 |
| 500 | 14.20653125 |
| 1,000 | 28.4130625 |
Common values
| Imperial fluid ounce | litre | |
|---|---|---|
| A teaspoon | 0.1759754 Imperial fluid ounce | 0.005 litre |
| A cup of coffee | 8.79876993 Imperial fluid ounce | 0.25 litre |
| A water bottle | 17.59753986 Imperial fluid ounce | 0.5 litre |
| A bathtub | 10,558.52391836 Imperial fluid ounce | 300 litre |
| A swimming pool (Olympic) | 87,987,699.31963512 Imperial fluid ounce | 2,500,000 litre |
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