Quick answer: An oil barrel is 42 US gallons, so 1 bbl = 158.98729 L; one cubic metre is 1,000 litres.
How it's calculated
The volume is changed to cubic metres, then to your unit. A litre is exactly one cubic decimetre (0.001 m³), so 1 m³ = 1,000 L and 1 mL = 1 cm³.
US and UK gallons differ: the US gallon is 231 in³ = 3.785411784 L, the UK (imperial) gallon is 4.54609 L. The fluid ounces differ too, and a US pint has 16 fl oz while a UK pint has 20.
Crude oil is quoted per barrel of 42 US gallons (158.987 L). Water tanks and desalinated water bills in the Gulf use litres, cubic metres or imperial gallons, so check which gallon a figure uses.
Worked examples
- One barrel of oil: 1 bbl = 158.98729 L
- A 5 m³ water tank: 5 m³ = 1,099.8462 UK gal
- A 20 L car fill-up: 20 L = 5.283441 US gal
Common volume conversions
| From | To |
|---|---|
| 1 US gal | 3.7854118 L |
| 1 UK gal | 4.54609 L |
| 1 L | 0.26417205 US gal |
| 1 bbl | 158.98729 L |
| 1 m³ | 1,000 L |
| 1 m³ | 6.2898108 bbl |
| 1 ft³ | 28.316847 L |
| 1 US fl oz | 29.57353 mL |
| 1 US cup | 236.58824 mL |
| 1 UK pt | 568.26125 mL |
Frequently asked questions
How many litres are in a gallon?
3.785 L in a US gallon and 4.546 L in a UK (imperial) gallon.
How many litres are in a barrel of oil?
One barrel is 42 US gallons, which is 158.987 L. A cubic metre holds about 6.29 barrels.
Is a millilitre the same as a cubic centimetre?
Yes. 1 mL = 1 cm³ exactly.
How many litres are in a cubic metre?
1,000. A 2 m³ rooftop tank holds 2,000 litres.
How many gallons are in a litre?
0.264 US gallons, or 0.220 UK gallons.
How many cups are in a litre?
Just over 4 US cups (about 4.23), or exactly 4 metric cups of 250 mL.