Fuel Cost Calculator
This fuel cost calculator works out how much a trip or a year of driving will actually cost, based on the distance you'll cover, your vehicle's real-world fuel efficiency, and the current price of fuel. Enter your numbers to see the total cost, how much fuel you'll need, and the cost per km — useful for budgeting a road trip, comparing two vehicles, or estimating your annual driving cost before deciding whether to buy or lease.
The total km for the trip, or your typical annual km if you are estimating a yearly fuel budget.
Your vehicle's real-world km/l — city driving typically runs 10–20% below the manufacturer's ARAI-rated figure.
The current price you pay at the pump. Petrol and diesel prices vary by state and city, so check today's local price rather than guessing.
Total fuel cost
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What you'll actually spend on fuel for the distance entered — e.g. ₹1,00,000/year driving 15,000 km at 15 km/l with ₹100/litre fuel.
The volume of fuel required — useful for planning fuel stops on a long trip or checking your tank capacity.
The best number for comparing vehicles — a pricier-to-fuel car can still cost less per km if it's more efficient.
How to use this fuel cost calculator
- 1Distance: total km for a single trip, or your typical annual km (check your last service record or odometer history) for a yearly estimate.
- 2Fuel efficiency: use your vehicle's real-world km/l, not the manufacturer's ARAI rating — highway km/l is usually close to the label, city km/l often runs 10–20% lower.
- 3Price per litre: use today's local price for the most accurate short-trip estimate; for an annual budget, use a rolling average since fuel prices fluctuate through the year.
- 4Compare the cost-per-km figure across two vehicles to see the real running-cost difference, not just the sticker km/l difference.
Understanding your results
Total fuel cost is the headline number — what you'll actually spend on fuel for the distance entered. Fuel needed shows the volume, useful for planning fuel stops on a long trip or checking your tank capacity is sufficient. Cost per km is the most useful number for comparisons: a more efficient but pricier-to-fuel vehicle can still cost more per km than a cheaper, less efficient one if fuel prices or driving style differ — always compare on cost per km, not on km/l alone.
The formula
Cost = (Distance ÷ km per litre) × Price per litreDistance divided by km-per-litre gives the litres of fuel required; multiplying by the price per litre gives the total cost. This is simple, linear arithmetic with no compounding — double the distance and the cost exactly doubles, all else equal. The only real-world complication is that km/l is not actually constant: it varies with driving style, terrain, load, tyre pressure and weather, which is why using a real-world (not manufacturer-rated) km/l figure matters for an accurate estimate.
A worked example
15,000 km a year at 15 km/l with fuel at ₹100/litre: fuel needed is 1,000 litres, for a total annual cost of ₹1,00,000 — a cost per km of ₹6.67. Compare a less efficient vehicle doing the same 15,000 km at 10 km/l and the same ₹100/litre: fuel needed rises to 1,500 litres, costing ₹1,50,000 a year — ₹50,000 more, purely from the efficiency difference, even though both vehicles cover identical distance.
Things to know
In India, fuel is priced per litre and efficiency is quoted in km per litre (km/l) — petrol and diesel prices are set daily and vary by state due to differing VAT rates, so the same trip can cost noticeably more in one state than another. Fuel cost is only part of total cost of ownership — insurance, maintenance and depreciation typically add more than fuel over a vehicle's life.
Frequently asked questions
How do I calculate fuel cost for a road trip?+
Divide the total trip distance by your vehicle's real-world km/l to get litres needed, then multiply by the price per litre. A 500 km trip at 15 km/l with ₹100/litre fuel costs about ₹3,333 — use the calculator above for your exact numbers.
Why is my actual fuel cost higher than the manufacturer's km/l suggests?+
ARAI ratings are measured under ideal test-track conditions. City driving, traffic, air conditioning, cargo load and aggressive acceleration can all cut real-world km/l by 10–20% or more below the certified figure — always budget using a real-world km/l, not the label.
How much does driving style affect fuel cost?+
Significantly — aggressive acceleration and braking can cut fuel efficiency by 15–30% in stop-and-go traffic, and highway speeds above roughly 100 km/h increase aerodynamic drag enough to noticeably reduce km/l. Smooth, moderate-speed driving is the single biggest free lever on fuel cost.
Is an electric vehicle cheaper than fuel per km?+
Usually yes on a pure energy-cost basis — electricity is typically cheaper per km than petrol or diesel, though the comparison depends heavily on local electricity tariffs and fuel prices. This calculator covers petrol/diesel vehicles; compare your local per-unit electricity price and vehicle efficiency (km/kWh) separately for an EV.
How do I estimate my annual fuel budget?+
Use your typical annual km (check your last two service records and subtract the odometer readings) as the distance, your real-world km/l, and an average fuel price across recent months rather than today's price alone, since prices fluctuate through the year.