1 barrel of crude oil = 158.98 liters, the density of crude oil is 0.99 kg/liter, and a barrel of oil is about 157 kg.

In oil exploitation, the earliest tool used to hold oil was indeed a barrel. But at that time, the bucket was just a load-bearing tool, not used to calculate the volume and so on. With the passage of time, many people have developed the habit of using barrel oil. Gradually, people get used to using barrels as the unit of measurement of oil.

Related introduction:

First of all, we should make clear the concept of "barrel". At present, each barrel is the most important pricing unit of crude oil futures, and the futures trading volume of several major crude oils accounts for almost all the market share. But some crude oil futures are not priced in barrels, just like the crude oil futures of Tokyo Stock Exchange in Japan are priced in kilograms. Many people may have the misunderstanding that crude oil is traded in barrels, because the price is calculated in barrels, which has also caused most people's misunderstanding. In fact, crude oil is mainly transported by pipeline, from oil fields to refineries or to export ports.

Directly transported to storage through local pipelines, barrels are basically just a unit of valuation, but actually it is not how much a barrel costs. Using "barrels" to measure the global coverage of crude oil is just like the status of the dollar. Crude oil can be said to be one of the few commodities with unified international pricing, and it is denominated in US dollars. Because most of the standards of the oil industry now come from the United States, and the United States is a big oil consumer, it still has a certain right to speak in this regard.

It is undeniable that the US dollar, as a global reserve currency, is more stable than other currencies. So it is understandable that crude oil will be priced in dollars.