Since April 2026, all petrol sold in India is E20 (20% ethanol blended petrol) — there is no more “pure” petrol option at the pump. Most drivers have noticed their mileage drop slightly, but few know exactly how much extra it’s costing them. This calculator converts the official mileage-loss estimates into real litres and real rupees for your car or bike.
E20 Fuel Mileage & Cost Impact Calculator
Govt estimate: 3-5% for most vehicles. SIAM estimate: 2-4% for BS6/post-2023 vehicles. Older pre-2023 vehicles have reported higher drops in owner surveys.
How E20 Mileage Loss Is Calculated
Step 1: Apply the Mileage Drop Percentage
New Mileage = Old Mileage x (1 - Loss %) Example: 15 km/L x (1 - 0.04) = 14.4 km/L
Step 2: Find Extra Litres Needed
Extra Litres = (Distance / New Mileage) - (Distance / Old Mileage) Example (1500 km/month): (1500/14.4) - (1500/15) = 104.2 - 100 = 4.2 litres extra
Step 3: Convert to Extra Cost
Extra Cost = Extra Litres x Price per Litre Example: 4.2 L x Rs.103 = Rs.433 extra per month (~Rs.5,200/year)
E20 Mileage Drop Reference Table
Baseline: 15 km/L old mileage, 1,500 km driven per month, petrol at Rs.103/litre.
| Mileage Drop | New Mileage | Extra Litres/Month | Extra Cost/Month | Extra Cost/Year |
|---|---|---|---|---|
| 2% (best case, new vehicle) | 14.7 km/L | 2.04 L | Rs.210 | Rs.2,524 |
| 3% (SIAM low estimate) | 14.55 km/L | 3.09 L | Rs.318 | Rs.3,822 |
| 4% (govt mid estimate) | 14.4 km/L | 4.17 L | Rs.429 | Rs.5,153 |
| 5% (govt high estimate) | 14.25 km/L | 5.26 L | Rs.542 | Rs.6,502 |
| 8% (older vehicle, real-world) | 13.8 km/L | 8.70 L | Rs.896 | Rs.10,748 |
| 10% (pre-2023 vehicle, upper range) | 13.5 km/L | 11.11 L | Rs.1,144 | Rs.13,733 |
Why Isn’t E20 Cheaper If It’s 20% Ethanol?
Even though ethanol is often assumed to be cheaper than petrol, the Ministry of Petroleum and Natural Gas has stated that E20 currently costs more to produce than pure petrol at prevailing crude prices — procurement, blending logistics, and ethanol production costs offset the fuel-cost savings. That’s why E20 is sold at the same pump price as regular petrol despite the lower energy content per litre: you pay the same price per litre but need more litres to travel the same distance.
Frequently Asked Questions
Is all petrol in India E20 now?
Yes. As of April 2026, petrol sold across India is E20 (20% ethanol blend) — there is no unblended “pure petrol” option left at fuel stations nationwide.
How much mileage does E20 actually reduce?
Government and SIAM estimates put the drop at 2-5% for most vehicles, especially those manufactured after 2023 with E20-tuned engines. Older, pre-2023 vehicles have reported higher drops (up to 10% or more) in owner surveys, since their engines weren’t originally calibrated for ethanol-blended fuel.
Does E20 damage older car engines?
An inter-ministerial government committee found no significant negative effect on metal or plastic components, drivability, or startability in field trials, including on legacy (pre-E20) vehicles. The main practical effect reported by owners is reduced mileage, not mechanical damage.
Why does E20 cost the same as regular petrol if ethanol is cheaper?
The government has stated E20 is currently more expensive to produce than pure petrol at current crude prices, due to ethanol procurement and blending costs — so the pump price stays the same even though you get fewer km per litre.
Can I improve my mileage on E20 fuel?
Yes — regular servicing, correct tyre pressure, smoother acceleration, and avoiding short trips with a cold engine can offset part of the E20 mileage loss, similar to any fuel-efficiency best practice.
Sources
- The Week — Govt admits E20 ‘may reduce’ mileage by 3-5%
- BusinessToday — Why E20 petrol is not cheaper despite 20% ethanol blending
- PSU Connect — E20 Petrol vs Normal Petrol: Mileage Drop, Engine Damage & Full Truth
Conclusion
E20 fuel’s 2-10% mileage drop (depending on your vehicle’s age) translates directly into extra litres and extra rupees every month. Use the calculator above with your own mileage and driving distance to see your real annual cost, and check our Fuel Cost Per KM Calculator or Gas Mileage Calculator for more fuel-budgeting tools. Also see our E20 vs CNG vs Diesel Running Cost Calculator. Also see our E20 vs Premium Petrol (XP95/XP100) Cost Calculator. Also see our E20 Fuel Additive & Octane Booster ROI Calculator.