India Petrol & Diesel Fuel Cost Calculator

The formula is: fuel cost = distance ÷ mileage × price per litre. So a 400 km trip in a car giving 18 km/L at ₹105/litre costs (400 ÷ 18) × 105 = ₹2,333. For a round trip, double the distance. If you're splitting with passengers, divide the total by the number of people sharing. The calculator handles all this in one go — just enter distance, mileage and current fuel price. Use realistic mileage figures (your actual experience, not the brochure number) for the most accurate estimate, especially for long highway runs.

Total fuel cost = (distance ÷ mileage) × fuel price per litre. The first part (distance ÷ mileage) tells you how many litres you'll burn; multiplying by the price gives the total spend. So for 200 km at 15 km/L with petrol at ₹100/litre, you need 200 ÷ 15 = 13.33 litres, costing ₹1,333. The same formula works for diesel (use diesel mileage and diesel price) or CNG (use km/kg mileage and price per kg). For round trips, multiply the distance by 2 before plugging in. Simple maths, but easy to forget when planning.

Divide 100 by your car's mileage (in km/L). So a car giving 20 km/L needs 100 ÷ 20 = 5 litres for 100 km. A 15 km/L car needs about 6.67 litres, and a 12 km/L SUV needs around 8.33 litres for the same distance. Real-world mileage usually drops 10-20% below the brochure figure, especially in city traffic with AC on. To get a true number, calculate from your last tank fill — divide kilometres driven by litres added. Then use that figure for trip planning, not the manufacturer's claim.

Cost per km = fuel price per litre ÷ mileage in km/L. So at ₹105/litre with 18 km/L mileage, your fuel cost works out to about ₹5.83 per km. Multiply by your monthly driving distance to estimate fuel spending — 1,500 km a month at ₹5.83/km is roughly ₹8,750. This is just fuel, of course; the true cost per km also includes insurance, maintenance, tyres and depreciation, which together can add another ₹3-8/km depending on the vehicle. Useful for trip budgeting, comparing cars, or deciding whether to drive vs taking a cab.

Calculate the total fuel cost for the trip first using distance, mileage and price. Then divide that figure by the number of people sharing. Decide upfront whether the driver pays a share too — if they're providing the car and doing the driving, splitting only among non-driver passengers is fairer. So a ₹2,400 fuel bill split four ways is ₹600 each; split among three passengers (driver covered by the others) is ₹800 each. For carpooling apps, fuel is just one cost — toll fees, parking and a small wear allowance are reasonable to include.

Match the mileage to the route. For a long highway trip with steady speeds and minimal stops, use the highway figure (usually higher — say 18-22 km/L for a typical petrol sedan). For city driving with traffic, signals and stop-start motion, use the city figure (often 12-15 km/L). For mixed routes, use the combined or average figure, or estimate weighted by how much of each you'll do. When in doubt, use the lower number — overestimating fuel cost is a smaller problem than running out of cash mid-trip. Real-world mileage almost always trails the lab number.

The full-tank method is the most reliable. Fill up completely, note the odometer reading, then drive normally until you need to fill up again. At the next fill-up, fill it back up to the same point (full tank) and note the litres added. Divide the kilometres driven (new odometer minus old) by the litres added — that's your real-world mileage. Repeat over a few tank cycles for a more reliable average, since one trip can be skewed by traffic or terrain. Most cars settle into a fairly consistent number once you know your driving pattern.

Yes — the same formula applies, you just need the right mileage and price unit. For diesel, use the car's km/L on diesel and the current diesel price per litre (usually a bit lower than petrol in India). For CNG, mileage is measured in km/kg (since CNG is sold by weight), and the price is per kg. So a CNG car giving 25 km/kg with gas at ₹85/kg costs about ₹3.40 per km. Always use the unit that matches the fuel — mixing litres and kilograms gives nonsense numbers. The calculator usually has separate fields for each fuel type.

The car's air conditioner runs off the engine via a belt-driven compressor, which adds extra load. The engine has to do more work for the same speed, so it burns more fuel — typically 5 to 15% more, depending on the car, the AC setting and the conditions. The drop is more noticeable in stop-start city traffic or hot weather (the AC works harder to cool the cabin). On the highway at steady speeds, the difference is smaller and usually worth it for comfort. Driving with windows down at high speeds adds drag, so AC often wins.

Calculate cost per km for each option. For petrol: ₹105/litre ÷ 16 km/L = ₹6.56/km. For diesel: ₹95/litre ÷ 22 km/L = ₹4.32/km. Multiply by your annual driving distance to see the yearly difference. So at 15,000 km/year, petrol costs ₹98,400 and diesel ₹64,800 — a saving of about ₹33,600 a year on diesel. But the diesel car usually costs ₹1-2 lakh more to buy and has slightly higher service costs. The break-even works out to about 4-5 years for high-mileage drivers. For low usage (under 10,000 km/year), petrol often makes more sense.