This converter turns oil barrels into US gallons instantly, using the exact factor 1 oil barrel = 42 US gallons. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
The petroleum barrel: 42 US gallons, the global oil trading unit. Exactly 231 cubic inches — the US liquid gallon used for fuel and milk.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
oil barrels- The amount you are converting, measured in oil barrels
42- The exact number of US gallons in one oil barrel
US gallons- The converted result
How it works, step by step
- Enter the number of oil barrels you want to convert.
- The value is multiplied by 42, the exact conversion factor.
- The result is displayed in US gallons, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 oil barrels
Multiply 5 by 42. That gives 210 US gallons. A quick sanity check: one oil barrel is larger than one US gallon, so the number should get bigger — and it does.
Converting 72 oil barrels
72 × 42 = 3,024 US gallons. Working backwards, 3,024 ÷ 42 returns 72 oil barrels, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many US gallons are in one oil barrel?
Exactly 42. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert oil barrels to US gallons?
Us Gallons = oil barrels × 42. To reverse it, divide instead: oil barrels = US gallons ÷ 42, which is the same as multiplying by 0.02380952381.
Is the oil barrel bigger than the US gallon?
Yes. One oil barrel equals 42 US gallons, so it is the larger unit.
Why does my answer differ slightly from other oil-barrels to us-gallons converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a oil barrel?
The petroleum barrel: 42 US gallons, the global oil trading unit.
What is a US gallon?
Exactly 231 cubic inches — the US liquid gallon used for fuel and milk.
Oil Barrels to US gallons reference table
| Oil Barrels | Us Gallons |
|---|---|
| 0.5 bbl | 21 gal |
| 1 bbl | 42 gal |
| 2 bbl | 84 gal |
| 3 bbl | 126 gal |
| 5 bbl | 210 gal |
| 10 bbl | 420 gal |
| 15 bbl | 630 gal |
| 20 bbl | 840 gal |
| 25 bbl | 1,050 gal |
| 50 bbl | 2,100 gal |
| 75 bbl | 3,150 gal |
| 100 bbl | 4,200 gal |
| 250 bbl | 10,500 gal |
| 500 bbl | 21,000 gal |
| 1000 bbl | 42,000 gal |
Exact factor: 1 oil barrel = 42 US gallons. Values rounded for display.