An oil barrel is 42 US gallons.
Oil barrels to Imperial gallons Converter — bbl to imp gal
Convert Oil barrel (bbl) to Imperial gallon (imp gal) using the exact conversion factor (1 oil barrel = 34.97231575 imperial gallon). See the formula, worked examples, conversion table, history, and common uses.
Oil barrels to Imperial gallons converter
Converter
Volume Converter
Convert metric, US customary, imperial, cooking, dry, and industrial volume units.
Context values
Some unit families need one extra value for a physically accurate result.
An imperial gallon is exactly 4.54609 liters.
Result = input x 0.1589872949 / 0.00454609.
Volume uses the cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Oil barrels to Imperial gallons
Oil barrel and Imperial gallon appear side by side at fuel pumps and on beverage labels, since the US measures liquids in gallons while most of the world uses liters. Specifically: An oil barrel is 42 US gallons, and an imperial gallon is exactly 4.54609 liters.
Formula
imperial gallons = oil barrels × 34.9723157544
This factor comes from each unit's defined relationship to the category's base unit: 1 oil barrel equals 0.158987294928 base units, and 1 imperial gallon equals 0.00454609 base units, so dividing one by the other gives the direct oil barrel-to-imperial gallon factor of 34.9723157544.
Simple example
1 bbl × 34.97231575 = 34.97231575 imp gal
1 oil barrel = 34.97231575 imperial gallons.
Real-world example
10 bbl × 34.97231575 = 349.7231575 imp gal
10 oil barrels = 349.7231575 imperial gallons.
Conversion table
| Oil barrel (bbl) | Imperial gallon (imp gal) |
|---|---|
| 1 bbl | 34.97231575 imp gal |
| 5 bbl | 174.8615788 imp gal |
| 10 bbl | 349.7231575 imp gal |
| 25 bbl | 874.3078939 imp gal |
| 50 bbl | 1,748.615788 imp gal |
| 100 bbl | 3,497.231575 imp gal |
Reverse conversion: Imperial gallon to Oil barrel
34.97231575 imp gal × 0.02859404585 = 0.9999999999 bbl
34.97231575 imperial gallons = 0.9999999999 oil barrels.
oil barrels = imperial gallons × 0.0285940458454
For a page dedicated to this direction, see Imperial gallon to Oil barrel.
Understanding the Oil barrel (bbl)
An oil barrel is 42 US gallons.
Understanding the Imperial gallon
Imperial gallon (imp gal) measures volume. The imperial gallon is defined as exactly 4.54609 liters, about 20% larger than the US gallon. It is classified as a UK/imperial customary unit.
Where it's used: United Kingdom, Canada (some contexts), and other Commonwealth countries
Imperial gallon vs. US gallon. Britain's 1824 Weights and Measures Act defined a new gallon based on 10 pounds of water, replacing the old wine gallon the US had already adopted — leaving the US (3.785 L) and imperial (4.546 L) gallons about 20% apart today.
Uses of the Imperial gallon today
- UK fuel and beverage measurement (historically; UK now primarily uses liters for retail)
- Commonwealth country liquid measurement in some contexts
History of the Imperial gallon
The imperial gallon was created by Britain's Weights and Measures Act of 1824, defined as the volume of 10 pounds of water, replacing several inconsistent older English gallon definitions (wine gallon, ale gallon, corn gallon) with one standard.
Historical origin. Imperial gallon was not the invention of a single named person; it developed through the process described above.
Imperial gallon — sources
- UK Weights and Measures Act 1824 — Establishes the imperial gallon definition.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many imperial gallons are in 1 oil barrel?
1 oil barrel equals 34.97231575 imperial gallons, using the exact defined conversion factor rather than an estimate.
How do I convert oil barrel to imperial gallon?
Multiply the oil barrel value by 34.97231575. The converter above does this instantly to whatever precision you set.
How do I convert imperial gallon back to oil barrel?
Use the reverse factor: 1 imperial gallon equals 0.0285940459 oil barrels. You can also use the swap control in the converter above to flip the direction instantly.
What is a oil barrel?
Oil barrel (bbl) is a unit of volume.
What is a imperial gallon?
Imperial gallon (imp gal) measures volume. The imperial gallon is defined as exactly 4.54609 liters, about 20% larger than the US gallon. It is classified as a UK/imperial customary unit.
Is the oil barrel to imperial gallon conversion exact?
Yes. The imperial gallon is defined as exactly 4.54609 liters, about 20% larger than the US gallon. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between imperial gallon vs. us gallon?
Britain's 1824 Weights and Measures Act defined a new gallon based on 10 pounds of water, replacing the old wine gallon the US had already adopted — leaving the US (3.785 L) and imperial (4.546 L) gallons about 20% apart today.