API level

API degree ( American Petroleum Institute degree; abbreviated form API ) is a conventional unit used in the USA for the density of crude oil . It is used around the world to characterize and measure the quality of crude oil and is usually added to the name of the variety .

The API degree results from the relative density of the crude oil (based on water) at 60  ° F (= 15 5/9 ° C):

${\displaystyle {\textrm {API-Grad}}={\frac {141{,}5}{\rho _{\mathrm {rel} }}}-131{,}5}$

It is called crude oil

• over 31.1 ° API as "easy"
• between 22.3 ° API and 31.1 ° API as "medium"
• below 22.3 ° API as "difficult".

See also

• Degree Baumé