Checked against the Marketing Discipline Guidelines 2024 (Ver. 1, effective 24.10.2024) on 26 October 2026. Published by MDG Services on 26 October 2026.
What the rules check instead of high or low
MDG sets a range for each fuel, then asks three questions. None asks for a higher or a lower number.
- Is the sample inside the range at 15°C? That is the specification a lab tests against MDG 7.6.
- Does the tanker match its invoice? The 15°C reading must be within ±3.0 kg/m³ of the invoice density MDG 1.2(iv). See the tanker density check.
- Is your own record on file? An inspector measures a sample from your outlet against the density you recorded for the tank MDG 2.10, and a missing record is an irregularity by itself MDG 5.1.9. See the 10 AM reference density.
| Fuel | Range at 15°C (kg/m³) | A reading outside it |
|---|---|---|
| Petrol (MS), every BS VI grade MDG names | 720–775 MDG 7.6 | Not to specification. Read both instruments again and convert again |
| Diesel (HSD), BS VI up to B7 | 810–845 MDG 7.6 | Not to specification. For fuel from Assam crude, Government of India notices may relax the range; ask your oil company MDG 7.6 |
| Diesel blended with biodiesel, B8–B20 | 820–860 MDG 7.6 | Not to specification. Check which blend you were supplied |
A mobile lab sample that fails on density brings the action for established adulteration MDG 7.4. The standards behind each range are on the density range page.
A lower reading is not a worse fuel
The same fuel reads lower on a hot afternoon than on a cool morning. For example (a made-up sample, worked out with the 15°C calculator): a petrol of 753.1 kg/m³ at 15°C reads 742.5 on the hydrometer at 27°C. Only the temperature changed, not the fuel. Convert before you judge a reading: see why density changes with temperature.
Questions dealers ask
01Diesel density should be high or low?
Neither. MDG gives BS VI diesel up to B7 a range of 810–845 kg/m³ at 15°C, and 820–860 for B8–B20 blends MDG 7.6. It does not call the top or the bottom of the range better. The dealer's check is a match with the invoice density within ±3.0 kg/m³ MDG 1.2(iv).
02Acche diesel ki density kitni honi chahiye?
810 to 845 kg/m³ at 15°C, or 820 to 860 for B8–B20 blends MDG 7.6. Any figure inside the range meets the density limit. The dealer's test is that the reading matches the invoice within ±3.0 kg/m³ MDG 1.2(iv).
03Petrol density which is good: higher or lower?
MDG gives petrol 720–775 kg/m³ at 15°C, the same for every BS VI grade it names, E20 included MDG 7.6. It does not rank one figure inside that range above another.
04Does petrol or diesel density change mileage?
MDG says nothing about mileage. General knowledge, not MDG text: a litre of denser fuel holds slightly more energy, so two lots at opposite ends of the range can differ a little. Driving, tyre pressure, load and engine condition usually matter more.
05Why does the hydrometer show a lower density in the afternoon?
Fuel expands when it warms, so the reading falls as the sample warms. Convert it to 15°C with the ASTM table before you compare it with anything MDG 1.2(iv) MDG 1.5(vi).
06If my density is inside the range, is the fuel certainly fine?
Not on that alone. The lab runs its other tests whatever the density result MDG 7.4, and a sample from your outlet is compared with the density you recorded for the tank MDG 2.10.
Read the official text: Marketing Discipline Guidelines 2024 (PDF on Bharat Petroleum's website) (also published on iocl.com).
Related pages
About Dealer Kavach (advertisement)
Dealer Kavach is an app from MDG Services that tracks your outlet's filings, renewals, inspections and daily reports, and reminds you before deadlines, in Hindi and English.