At 15 °C, BS-VI petrol must be between 720 and 775 kg/m³ (IS 2796) and BS-VI diesel between 810 and 845 kg/m³ (IS 1460). The oil companies list these limits in their Marketing Discipline Guidelines. Most petrol sits around 740 to 755 and most diesel around 825 to 835.
The limits
| Fuel | Standard | Density at 15 °C |
|---|---|---|
| Petrol (MS), BS-VI, and E10 to E20 | IS 2796 | 720 to 775 kg/m³ |
| Diesel (HSD), BS-VI, up to B7 | IS 1460 | 810 to 845 kg/m³ |
| Biodiesel blends B8 to B20 | IS 16531 | 820 to 860 kg/m³ |
MDG 2024 notes that a relaxation of the diesel density range may apply to fuel processed from Assam crude, as notified by the Government.
Why the ranges matter at the pump
The limits are wide enough to cover every refinery’s output, so a reading inside them does not prove the fuel is right. The check that catches mixing is the ±3.0 kg/m³ comparison with the invoice, and the comparison of each morning’s density with the last load’s. A reading outside the range, though, is a clear sign: stop, take a fresh sample, and call your sales officer.
Weight of a litre
Density in kg/m³ divided by 1,000 is kg per litre. A litre of petrol at 15 °C weighs 0.720 to 0.775 kg; a litre of diesel 0.810 to 0.845 kg. See the litres to kg calculator.
Figures here are for reference. Your oil company’s certified calibration chart, approved instruments and the Marketing Discipline Guidelines always prevail.
Questions
Why has the diesel lower limit changed?
Under BS-IV the diesel range was 820 to 845 kg/m³. The BS-VI specification lowered the bottom to 810 kg/m³.
Is blended petrol (E10, E20) in the same range?
Yes. MDG 2024 lists 720 to 775 kg/m³ for motor gasoline and for the ethanol blends E10 to E20 alike.
My reading is 12 kg/m³ off yesterday's. Is that wrong?
Compare density at 15 °C, never raw hydrometer readings. A raw reading drops by roughly 0.7 to 0.9 kg/m³ for every degree warmer. If the figures at 15 °C differ that much, check the jar, the hydrometer and the sample.