Petrol vs Diesel vs CNG vs Electric: Real Running Cost per KM in India 2026

On today's Delhi pump prices, an electric car charged at home is by far the cheapest thing to drive, at roughly ₹1.2 per kilometre. CNG follows at about ₹3.2/km, diesel at ₹4.5/km and petrol at ₹5.7/km. Put plainly, a petrol car costs almost five times as much per kilometre as an EV topped up on home power. But the pump price is only half the story: an EV on public fast charging climbs back to around ₹3/km, and diesel, CNG and electric cars all cost more to buy in the first place. Here is the honest, city-by-city math for 2026, with every assumption printed on the chart.

Delhi prices, 25 August 2026. Efficiency assumed: petrol 18 km/L, diesel 21 km/L, CNG 26 km/kg, EV 6.5 km/kWh on a home tariff of about ₹8 per unit. Change the city or the efficiency and the rupee figures shift, but the running order barely moves.

What fuel actually costs across India today

As of 25 August 2026, petrol is cheapest in Delhi at ₹102.12 a litre and dearest in Hyderabad at ₹115.69, with Mumbai, Chennai, Kolkata and Bengaluru all sitting between ₹107 and ₹114. Diesel has been steadier: the 25 August rate is unchanged from the 25 May 2026 revision, at ₹95.20 in Delhi, ₹97.83 in Mumbai and ₹103.82 in Hyderabad. CNG is where the gap really opens up, at ₹83.09 per kg in Delhi and ₹86 in Mumbai, though it climbs to ₹97.5 in Pune, ₹97 in Bengaluru and ₹109 in Hyderabad. The spread comes down to local VAT and transport, which is why the same fuel can cost ₹13 more per litre one state over.

Cost per kilometre: the number that actually matters

A litre price tells you nothing on its own; what matters is how far that litre, kilo or unit carries you. Divide each Delhi fuel price by a realistic efficiency and the picture snaps into focus. Petrol at 18 km/L works out to about ₹5.7 per kilometre. Diesel at 21 km/L drops to ₹4.5. CNG at 26 km/kg falls to ₹3.2. And an EV doing 6.5 km per kWh, charged overnight at roughly ₹8 a unit, costs a remarkable ₹1.2 per kilometre. Whatever you drive, the cheapest saving of all is free air: under-inflated tyres raise rolling resistance and quietly cost you 3 to 5 percent in mileage, so a boot-friendly tyre inflator that keeps every tyre at the door-sticker pressure pays for itself in saved fuel.

Two things jump out. First, the EV on home power is in a class of its own, roughly a fifth of the running cost of petrol. Second, once you plug into a public DC fast charger at ₹18 to 24 a unit, the EV lands at about ₹3 a kilometre, almost exactly level with CNG. So the EV's headline cheapness is real, but it depends heavily on where you charge.

The honest caveats before you switch

Running cost is not the same as the cost of owning a car. Diesel, CNG and electric cars usually cost more to buy than an equivalent petrol model, and each carries its own upkeep: diesels have pricier servicing, CNG kits need periodic checks, and an EV battery is a long-term replacement cost you should factor in. A CNG car only delivers that ₹3.2 per km when the kit is healthy and the tyres are correctly inflated, which is exactly where a compact digital tyre inflator or an all-in-one jump starter with a built-in pump earns its place in the boot for the occasional roadside top-up or a flat battery on a cold morning.

• Where you charge decides everything for an EV: ₹1.2/km at home, but around ₹3/km on public fast charging.
• Upfront cost: diesel, CNG and EV models typically carry a higher sticker price than petrol, so the per-km saving takes time to pay back.
• Maintenance: diesel servicing, CNG kit checks and eventual EV battery replacement are real costs the per-km figure ignores.
• Your real mileage varies: city crawl, AC use, load and tyre pressure all move the numbers, so treat these as a fair benchmark, not a guarantee.

None of this changes the ranking, but it does change the payback maths. If you drive a lot, the cheaper per-km fuels recover their price premium faster; if you drive little, a plain petrol car can still work out cheaper overall. And whatever you own, the boring habits, correct tyre pressure, a clean air filter and a car you actually keep in shape with something as simple as a cordless vacuum, protect the efficiency you paid for.

Frequently asked questions