A standard barrel of crude oil holds 42 US gallons , which is about 159 liters (often written as 158.99 L).

Quick Scoop: How Much Oil Is in a Barrel?

If you’ve heard oil prices quoted “per barrel” and wondered what that actually means, here’s the simple breakdown.

The basic number

  • One standard oil barrel = 42 US gallons of crude oil.
  • In metric terms, that’s roughly 159 liters (more precisely 158.99 L at standard conditions).
  • This “standard barrel” definition assumes about 60°F (15.6°C) and normal atmospheric pressure, which is how the industry keeps measurements consistent.

So when the news says “oil is $80 per barrel,” they mean $80 for 42 gallons of crude oil , not a physical wooden barrel anymore.

Extra: Refined products from one barrel

Because of refining, that 42-gallon barrel of crude can be turned into about 45 gallons of refined products like gasoline, diesel, jet fuel, and others. This happens because some processes expand the volume slightly as lighter products are created.

“How much oil is in a barrel?”
Answer: 42 gallons (≈159 liters) of crude oil by industry standard.

TL;DR: A barrel of oil is a measurement unit , not a physical drum: 42 US gallons ≈ 159 liters of crude oil , defined at standard temperature and pressure.

Information gathered from public forums or data available on the internet and portrayed here.