How many gallons are in one oil barrel?

One US oil barrel (bbl) equals exactly 42 US liquid gallons. This is the standard petroleum barrel defined by the API and used in US crude oil trading, production statistics, and refinery reporting.

How many liters are in one oil barrel?

One US oil barrel equals approximately 158.987294928 liters (L). This follows from 42 US gallons × 3.785411784 L/gal.

Why is an oil barrel 42 gallons and not some round number?

The 42-gallon oil barrel was standardized in the 1860s by Pennsylvania oil producers. It was based on the common wine tierce (42 gallons) that was already in wide use, and the size stuck as the industry adopted it as the global petroleum trading standard.

Is a barrel of oil the same as a barrel of beer or a barrel of water?

No. A US oil barrel is 42 US gallons. A US beer barrel is 31 US gallons. A US fluid barrel is 31.5 US gallons. Always specify "oil barrel" or "petroleum barrel" (bbl) when working with crude oil volumes to avoid confusion.

How do I convert barrels per day (bbl/day) to gallons per day?

Multiply bbl/day by 42. For example, 1,000 bbl/day × 42 = 42,000 gallons/day. The conversion factor is the same as for a single barrel.

Barrels to Gallons (Oil)

Name: Barrels to Gallons (Oil)
Availability: InStock
Author: Nham Vu

Enter petroleum barrels (bbl) and get US gallons and liters instantly — 1 oil barrel = 42 US gallons exactly.

Converter

Oil barrels (bbl)

= — US gallons

= — liters (L)

US gallons — reverse

= — barrels (bbl)

Liters — reverse

= — barrels (bbl)

1 bbl (oil) = 42 US gal exactly | 1 bbl = 158.987294928 L

Common conversions

Barrels (bbl)	US Gallons	Liters

About the oil barrel

The US petroleum barrel (bbl) is defined as exactly 42 US liquid gallons. This standard was set by Pennsylvania oil producers in the 1860s and remains the global unit for crude oil trading, OPEC production data, and US EIA statistics.

Summary

Enter petroleum barrels (bbl) and get US gallons and liters instantly — 1 oil barrel = 42 US gallons exactly.

How it works

Enter a barrel (bbl) value in the top input field.
US gallons and liters results appear instantly — no button needed.
Use the reverse fields to convert gallons or liters back to barrels.
The reference table shows common bbl values at a glance.
Click "Copy" next to any result to copy it to your clipboard.

Use cases

Convert crude oil purchase volumes from barrels to gallons for storage planning.
Translate pipeline throughput figures between bbl/day and gallons/day.
Calculate fuel costs when prices are quoted per gallon but volumes are in barrels.
Verify petroleum invoice quantities between barrel and gallon denominations.
Convert oil production reports between US customary units.
Cross-check refinery output figures in different unit systems.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu