E20 Mileage Impact Calculator

Yes, because ethanol carries about 65% of the volumetric energy of petrol. When your tank has 20% ethanol, the fuel delivers less energy per litre, so the engine burns more fuel to cover the same distance. The official range from NITI Aayog and ARAI is 1–7% depending on how well your engine is calibrated for E20: roughly 1–2% for fully E20-compliant vehicles, 2–6% across real-world fleet tests, and up to 6–7% for older cars designed for E0 and never re-tuned for higher ethanol.

E20 — petrol blended with 20% ethanol — is being rolled out as India's standard petrol under the Ethanol Blended Petrol (EBP) Programme. The government advanced its target for nationwide 20% average blending from 2030 to 2025–26, and India reached roughly 20% average ethanol blending in 2025. It is not a law that bans older vehicles, but as E20 progressively replaces E10 at pumps, most petrol sold is becoming E20. If your vehicle isn't tuned for E20, use the slider above to estimate your own mileage and cost impact.

E20 petrol was first launched on 6 February 2023 at India Energy Week in Bengaluru, initially at 84 fuel outlets across 11 states and union territories. Oil marketing companies have widened availability every year since as the country moves toward 20% ethanol blending, so E20 is now sold at a growing share of petrol stations across India.

It depends on your car's mileage, monthly distance and the efficiency drop applicable to your engine. At the default 3.5% drop (the calorific-value delta for an E10→E20 switch), a car giving 20 km/L driven 1,000 km/month at ₹105/L incurs roughly ₹190 extra per month and ₹2,285 per year. Enter your own numbers in the calculator above for a personalised figure.

Pure ethanol has a lower heating value — about 21 MJ per litre versus roughly 32 MJ per litre for petrol. A 20% ethanol blend therefore delivers less energy per litre of fuel, forcing the engine to consume more litres to produce the same power. This physical mechanism is confirmed by the IEA Advanced Motor Fuels programme and the US Department of Energy's Alternative Fuels Data Center.

Use the slider in the calculator to pick the figure closest to your vehicle: 1–2% if your car was designed and tuned specifically for E20 (newer models); 3–3.5% if you are switching from E10 (the calorific-value ceiling stated by Maruti Suzuki); 2–6% for a typical car aged 3–10 years based on ARAI's real-world fleet tests; and up to 6–7% if your car was originally designed for E0 petrol and has never been re-calibrated for higher ethanol content.

ARAI tested passenger vehicles and two-wheelers over 40,000 km and 20,000 km respectively and found that E20 does not cause engine failure or major performance issues in compatible vehicles — drivability, startability and acceleration were unaffected. The concern is limited to fuel economy: older, non-E20-calibrated engines burn more fuel. Check your vehicle's owner manual or manufacturer guidance to confirm E20 compatibility.

India's National Biofuel Policy mandates progressive ethanol blending, with 20% blending (E20) targeted nationwide by 2025–26. As E20 replaces E10 at pumps, it will increasingly be the only petrol available at most fuel stations. If your vehicle is not E20-compatible, consult your manufacturer about the impact and any available recalibration.

For the average driver switching from E10 to E20, the calorific-value drop is about 3–3.5%, so a car that gives 20 km/L on E10 would give roughly 19.3–19.4 km/L on E20. ARAI's broader fleet testing found the real-world range to be 2–6% across vehicles aged 3–10 years, meaning the same 20 km/L car could register 18.8–19.6 km/L depending on engine calibration.

E20 mein 20% ethanol hota hai, jiska energy content petrol se kareeb 35% kam hota hai per litre (IEA-AMF ke anusar). Iska matlab hai ki ek litre E20 se utni energy nahi milti jitni ek litre E10 se milti thi, is liye engine ko same distance cover karne ke liye zyada fuel jalana padta hai. NITI Aayog aur ARAI dono ne confirm kiya hai ki mileage mein 2–7% ki kami typical hai — yeh depend karta hai aapki gaadi ke engine calibration par.

NITI Aayog estimates a 3–4% efficiency loss for two-wheelers designed for E0 and calibrated for E10 when running E20, compared to 6–7% for similar four-wheelers. ARAI's combined fleet tests (two-wheelers over 20,000 km) show mileage drops are in a similar range to cars. Two-wheelers designed for E20 see the same 1–2% loss as compliant four-wheelers.

Yes. Manufacturers are increasingly producing vehicles designed and calibrated for E20 from the factory. SIAM has noted that hardware and tuning modifications can significantly reduce or eliminate the efficiency penalty. Newer E20-ready vehicles should settle in the 1–2% range rather than the 3–7% range seen in older engines, so the loss will narrow across the fleet as the vehicle parc turns over.

Currently in India, E20 is priced the same as regular petrol at the pump. The calculator assumes price parity, meaning the only cost change is the extra fuel you burn due to lower efficiency. If the government introduces a price differential in future, the actual extra cost per month could differ from this calculator's output.

The arithmetic is exact: extra litres = monthly distance × (1/E20-efficiency − 1/baseline-efficiency), and extra cost = extra litres × pump price. The main uncertainty is the efficiency-drop percentage, which the official sources express as a range (1–7%) because it depends on your engine's calibration for ethanol. By letting you set the drop percentage, the calculator personalises the result to your situation rather than applying a one-size-fits-all official figure.