How Many Gallons Are in a Barrel of Oil?

By custom. NIST Handbook 44 says that by custom, 42 gallons make a barrel of crude oil or petroleum products for statistical purposes. The EIA glossary gives the same size.

The same handbook notes that laws and industries use barrels of other sizes. So the 42-gallon figure belongs to oil and petroleum products, not to every barrel you might see.

Picture 42 one-gallon jugs lined up on a shelf. The same amount would fill about 79 two-liter bottles or 8.4 five-gallon buckets.

In kitchen measures, that is 672 cups. The table above lists the barrel in quarts, pints and fluid ounces as well.

Multiply the number of barrels by 42 to get US gallons, or by 158.99 to get liters. For UK (imperial) gallons, multiply by 34.97.

To go from gallons back to barrels, divide by 42. For example, 1,000 gallons is 23.8 barrels. The gallons to liters converter handles the metric side for any amount.

The same math works for a price. If you see an oil price per barrel, divide it by 42 for the price per US gallon, or by 158.99 for the price per liter. That is the cost of the crude oil itself, before it is refined, so it is not the price of gasoline at the pump.

More than 42 gallons of products. In 2023, US refineries produced an average of about 45 gallons of refined products for every 42-gallon barrel of crude oil, according to the EIA.

The EIA calls this extra volume processing gain. It averaged about 6.3% at US refineries that year, which is why the products in the table add up to more than the barrel itself.

Gasoline is the largest single product. Distillate fuel oil, which is mostly diesel, comes next, and jet fuel is a smaller share. These are 2023 averages, the latest year on that EIA page when we checked.