Reference Library
Temperature Conversions
Pressure Conversions
Length Conversions
Specific Gravity of Oil
| Type of Oil | Temp | kg m-3 | SG at 60°F |
| Crude oil, 48° API | 60°F | 790 | 0.7883 |
| Crude oil, 40° API | 60°F | 825 | 0.8251 |
| Crude oil, 35.5° API | 60°F | 847 | 0.8473 |
| Crude oil, 32.5° API | 60°F | 862 | 0.8628 |
| Crude oil, California | 60°F | 915 | |
| Crude oil, Mexican | 60°F | 973 | |
| Crude oil, Texas | 60°F | 873 |
API gravity formulas
The formula used to obtain the API gravity of petroleum liquids is:
API gravity = (141.5/SG at 60°F) - 131.5
Conversely, the specific gravity of petroleum liquids can be derived from the API gravity value as:
SG at 60°F = 141.5/(API gravity + 131.5)
60°F (or 15.5556°C) is used as the normal value for measurements and further tables give adjustments for temperature
(as determined by ASTM D1298).
Thus, a heavy oil with a specific gravity of 1.0 (i.e., with the same density as pure water at 60°F) would have an API gravity of
(141.5/1.0) - 131.5 = 10.0 degrees API.

