Convert API gravity to density or density to API using kg/m³, lb/ft³, or g/cm³ units for petroleum fluids at a 60°F reference quickly.
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Density From API Formula
The following formula is used to calculate the Density From API.
D = 141.5/(API+131.5) * 998.9
- Where D is the Density From API (kg/m^3)
- API is the API
| API (°API) | Density (kg/m³) | Density (lb/ft³) | Density (g/cm³) |
|---|---|---|---|
| 8 | 1013.221 | 63.253 | 1.013 |
| 10 | 998.900 | 62.359 | 0.999 |
| 12 | 984.975 | 61.490 | 0.985 |
| 15 | 964.783 | 60.230 | 0.965 |
| 18 | 945.449 | 59.023 | 0.945 |
| 20 | 932.963 | 58.243 | 0.933 |
| 22.3 | 919.028 | 57.373 | 0.919 |
| 25 | 903.135 | 56.381 | 0.903 |
| 28 | 886.174 | 55.322 | 0.886 |
| 30 | 875.196 | 54.637 | 0.875 |
| 31.1 | 869.214 | 54.263 | 0.869 |
| 32 | 864.506 | 53.969 | 0.865 |
| 35 | 848.915 | 52.996 | 0.849 |
| 37 | 838.839 | 52.367 | 0.839 |
| 40 | 824.267 | 51.457 | 0.824 |
| 42 | 814.665 | 50.858 | 0.815 |
| 45 | 800.528 | 49.975 | 0.801 |
| 50 | 778.812 | 48.620 | 0.779 |
| 55 | 757.965 | 47.318 | 0.758 |
| 60 | 737.827 | 46.061 | 0.738 |
| * Rounded to 3 decimals. Formula used: ρ (kg/m³) = 141.5 / (API + 131.5) × 998.9 (at 60°F). Unit conversions: 1 lb/ft³ = 16.0185 kg/m³; 1 g/cm³ = 1000 kg/m³. | |||
How to Calculate Density From API?
The following example problems outline how to calculate Density From API.
Example Problem #1:
- First, determine the API.
- The API is given as: 55.
- Finally, calculate the Density From API using the equation above:
D = 141.5/(API+131.5) * 998.9
The values given above are inserted into the equation below:
D = 141.5/(55+131.5) * 998.9 = 757.878 (kg/m^3)
Example Problem #2:
For this problem, the variables needed are provided below:
API = 65
This example problem is a test of your knowledge on the subject. Use the calculator above to check your answer.
D = 141.5/(API+131.5) * 998.9 = ?
