What’s the Difference Between a Barrel and a Drum

Any time there is news about the price of oil, we always hear it measured “per barrel.” So why are cylindrical steel containers that hold oil called “drums?” What’s the difference between a drum and a barrel, anyway?

The word “barrel” conjures up the image of a cylinder made of wood staves, bound with metal hoops. A barrel is a cask-like container that’s fatter in the middle than at the ends, and longer than it is wide.

The “barrel” referred to when discussing the price of oil is an internationally established unit of measurement. One barrel is 42 US gallons, or 35 Imperial gallons (UK). Crude oil isn’t actually transported in barrels; it gets shipped in giant tankers. But the oil industry defines how much is in that ship by how many “barrels” it carries.

But you may not always think of oil when someone uses the word “barrel.” You may picture wine or whiskey aging in oak barrels. If you’re into metalworking, jewelry-making, or geology, a “barrel” to you is a tumbler, to polish and shine metal or semi-precious stones.

Drums, on the other hand, are used for shipping all kinds of materials. There is no internationally established volume for a drum, but most hold 55 gallons. Drum manufacturers make different sizes for different purposes. For example, they also make smaller ones that hold 30 gallons.

In addition to the steel drums used for transporting hazardous or flammable materials, there are drums made of paperboard—called fiberboard—and drums made of heavy-duty, UV resistant plastic. Fiberboard reduces the cost of shipping because it’s lighter. Most parts of fiber drums are recyclable. They can transport a variety of goods, but can’t handle the hazardous materials steel drums can.

People often call a drum a barrel, but rarely call a barrel a drum. The only time the difference between a barrel and a drum matters is when you need to know how much the cylindrical container holds— and the price of oil.

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