Barrels to Gallons Converter

The term "barrel" is ambiguous. Select the type of barrel you want to convert to instantly see the result in US gallons.

Which "Barrel" Are You Converting?

Unlike units like "meter" or "kilogram," the "barrel" is not a single defined unit. Its volume depends entirely on the context. Our calculator defaults to the **US Oil Barrel**, which is the most common international standard, but you may be referring to one of several others.

Conversion Formulas

Here are the exact conversion factors used by this calculator:

• 1 US Oil Barrel (bbl) = 42 US Gallons
  This is the standard for measuring crude oil and other petroleum products.
• 1 US Liquid Barrel = 31.5 US Gallons
  This is a less common standard, sometimes used for other liquids like chemicals or food products.
• 1 US Beer Barrel = 31 US Gallons
  This unit is legally defined in the US for tax purposes related to beer.
• 1 US Dry Barrel = 105 dry quarts (28.378 US Gallons)
  Used for some dry goods.
• 1 UK (Imperial) Barrel = 36 Imperial Gallons (43.234 US Gallons)
  Used in the United Kingdom. Note that an Imperial gallon is larger than a US gallon.

Conversion Table (Oil Barrels)

This table shows the conversion for the most common unit, the US Oil Barrel (bbl).

Frequently Asked Questions (FAQ)

How many gallons are in a barrel of oil?

There are exactly **42 US gallons** in one standard barrel of oil (bbl).

How many gallons are in a barrel of beer?

In the United States, a standard barrel of beer is **31 US gallons**. This is different from a "keg," which is typically a half-barrel (15.5 gallons).

Why is an oil barrel 42 gallons?

The 42-gallon standard dates back to the 1870s in Pennsylvania. Early oil producers used 42-gallon wooden barrels (originally used for whiskey) for transport. This size became the standard for the industry to avoid disputes and ensure consistent measurement for trade.