About

In the global energy market, crude oil is often traded by the barrel (volume) but shipped by the tonne (mass). This creates a conversion necessity that is dependent on the specific density of the oil. Unlike water, oil expands and contracts significantly with temperature and varies chemically by source (Light vs. Heavy Crude).

This professional converter uses the API Gravity scale - the industry standard for petroleum density - to derive the Specific Gravity (SG) and calculate the precise number of barrels per metric tonne. It is essential for traders, logistics coordinators, and refinery planners handling diverse crude grades.

Formulas

The conversion is a two-step process. First, API Gravity is converted to Specific Gravity (SG) at 60°F.

SG = 141.5API + 131.5

Then, the mass is converted to volume using the standard barrel factor (1 barrel ≈ 158.987 liters) adjusted for density.

bbl = Tonnes × 1SG × 6.293

Reference Data

Crude Type	API Gravity	Specific Gravity (SG)	Barrels per Tonne
Extra Heavy	10.0	1.000	6.29
Heavy	20.0	0.934	6.74
Medium	30.0	0.876	7.18
Light (WTI)	40.0	0.825	7.63
Super Light	45.0	0.802	7.85
Condensate	55.0	0.759	8.29

Frequently Asked Questions

API Gravity is an inverse measure of the density of a petroleum liquid relative to water. If API > 10, it floats on water; if API < 10, it sinks. Higher API values indicate lighter, more valuable crude oil.

This constant is derived from the definition of a barrel (42 US gallons) and the density of water at 60°F. Since Specific Gravity is relative to water, this constant aligns the metric tonne (1000kg) to the barrel volume unit.

Yes. This calculator assumes standard conditions (60°F / 15.6°C). In operational contexts, Volume Correction Factors (VCF) from ASTM tables must be applied to account for thermal expansion.