Fuel Cost Calculator
Calculate the fuel cost of any trip from distance, mileage and fuel price, plus litres needed and cost per km.
Formula last reviewed 15 September 2026 · How we verify our calculators
Total fuel cost
- Fuel needed
- 20
- Cost per km
- ₹7
Updates live as you type
Frequently asked questions
Litres needed is distance divided by mileage, and total cost is litres multiplied by price per litre. A 300 km trip at 15 km/L with fuel at 100 a litre needs 20 litres and costs 2,000. The more useful derived figure is cost per kilometre, which is simply price divided by mileage — 6.67 per km here — because it is independent of trip length and lets you price any journey mentally.
Because ARAI figures in India are measured on a controlled laboratory test cycle, not on real roads. Real-world results typically run 15-25% below the quoted number, and the gap widens in city traffic. To find your actual figure, fill the tank completely, reset the trip meter, drive normally until the tank is low, fill completely again, and divide kilometres travelled by litres needed to refill. Do it twice for a reliable average.
Driving conditions dominate. City driving typically returns 20-30% less than highway driving because of idling, stop-start movement and low gears. Air conditioning costs roughly 5-10%. A fully loaded car with roof luggage can lose 10-20%. Efficiency generally peaks around 60-80 km/h and falls off noticeably above 100. Tyres under-inflated by 25% cost another 3-5%, which makes pressure the cheapest efficiency gain available.
It depends almost entirely on how many people travel. A 300 km trip costing 2,000 in fuel is 2,000 for one person, 1,000 each for two, or 500 each for four — so a car becomes competitive with train fares quickly as occupancy rises. The comparison is only fair if you also add tolls, which can run 1.50-2.50 per kilometre on tolled highway stretches, plus parking at the destination.
No, it covers fuel only. For a full picture of a road trip, add tolls, parking and any overnight stops. And for deciding whether driving is genuinely cheap, note that fuel is roughly half the true running cost of a car once maintenance, tyres, insurance and depreciation are apportioned across the kilometres — an all-in figure for a petrol hatchback is closer to 10-14 per kilometre than the 6.67 of fuel alone.
Multiply the per-kilometre difference by your realistic annual distance. Moving from 15 km/L to 20 km/L at 100 a litre takes cost per kilometre from 6.67 to 5.00, so over 15,000 km a year that is 25,000 saved annually, or 1,50,000 across six years of ownership. Note that mileage sits in the denominator, so gains matter less as efficiency rises: going from 10 to 15 km/L saves far more than going from 25 to 30.
Because state VAT on petrol and diesel varies considerably, and it is levied on top of the central excise duty and the base price. That is why the same fuel can cost several rupees more per litre across a state border, and why filling up before crossing into a higher-tax state is a genuine if marginal saving. Enter today's local price rather than a remembered figure, since prices are revised frequently.
Yes, and it is common. A highway bypass that adds 40 kilometres but avoids dense city traffic can consume less fuel than the shorter route, because stop-start driving at low speeds is dramatically less efficient than steady cruising. It usually saves time as well. When comparing routes, compare estimated fuel and time rather than distance alone, particularly where the shorter option runs through a city centre.
Both have a substantially lower cost per kilometre — CNG typically around half that of petrol, and an EV charged at home often a quarter or less. The comparison is not complete at the pump, though. CNG involves a conversion or purchase premium and a significant loss of boot space, while an EV carries a higher upfront price, battery replacement risk over a long horizon, and depends on charging access. Work out the per-kilometre saving, then divide the premium by it to see the break-even distance.
What the trip actually costs to drive
A 300 km journey in a car returning 15 km/L, with fuel at ₹100 a litre, needs 20 litres and costs ₹2,000 — about ₹6.67 per kilometre.
Improve the mileage to 20 km/L and the same trip needs 15 litres and costs ₹1,500, or ₹5.00 per kilometre. That five-kilometre-per-litre difference is worth ₹500 on one trip, and for someone driving 15,000 km a year it is the difference between ₹1,00,000 and ₹75,000 in annual fuel — ₹25,000 a year, every year, decided at the moment of purchase.
Fuel is usually the largest running cost of a vehicle and the one people estimate worst, because it is paid in small instalments at a pump rather than as a visible annual bill. Converting it to a per-kilometre figure is what makes it comparable against a train fare, a cab quote, or another car.
The calculation
Two steps, and one useful shortcut.
Litres needed = distance ÷ mileage
Total cost = litres × price per litre
Combined: Cost = (distance ÷ mileage) × price
The shortcut worth memorising is the per-kilometre rate, because it is independent of trip length:
Cost per km = price per litre ÷ mileage
At ₹100 a litre and 15 km/L that is 100 ÷ 15 = ₹6.67/km. Once you know your own figure you can price any journey in your head — a 40 km commute costs about ₹267 of fuel each way.
Note that mileage sits in the denominator, which is why improvements matter less as efficiency rises. Going from 10 to 15 km/L saves ₹3.33 per kilometre. Going from 25 to 30 km/L — the same five-unit gain — saves only ₹0.67. The first few kilometres per litre are worth far more than the last few, which is the honest case for why upgrading from a very inefficient vehicle pays back quickly while chasing marginal efficiency at the top end rarely does.
Working through the numbers
Distance 300 km, mileage 15 km/L, fuel ₹100/L.
Step 1. Litres = 300 ÷ 15 = 20 litres.
Step 2. Cost = 20 × 100 = ₹2,000.
Step 3. Per km = 100 ÷ 15 = ₹6.67.
Comparing against alternatives for the same 300 km:
Fuel alone is ₹2,000, so two people in the car travel at ₹1,000 each and four people at ₹500 each. That is the calculation that decides most family trips — a car becomes cheaper than four train tickets surprisingly quickly, and cheaper than four flights almost always.
But fuel is not the full cost of driving. Add tolls, which on national highways can run ₹1.50–₹2.50 per kilometre on tolled stretches, parking, and — for an honest comparison — the share of maintenance, tyres and depreciation attributable to those kilometres. A rough all-in running cost for a petrol hatchback is closer to ₹10–₹14 per kilometre than the ₹6.67 of fuel alone. For a one-off trip the fuel figure is the right one to use, since the other costs are largely fixed; for deciding whether to own a car at all, it badly understates the position.
When to run this
Before a road trip, to budget fuel separately from tolls and stops.
When comparing driving against a train, bus or cab. Divide the fuel cost by the number of people travelling — that is the number that competes with a ticket price.
When choosing between two vehicles. Multiply the per-kilometre difference by your realistic annual distance, then by how long you expect to keep the car. A ₹1.67/km gap over 15,000 km a year for six years is ₹1,50,000.
When deciding whether a longer route is worth it. A highway detour that adds 40 km but avoids city traffic may use *less* fuel, because stop-start driving is far less efficient than steady cruising.
For expense claims, where reimbursement is usually per kilometre and worth checking against actual cost.
Reading your result
The total cost assumes your entered mileage is what the vehicle actually delivers. It very often is not. Manufacturer-quoted ARAI figures in India are measured under controlled laboratory conditions and are routinely 15–25% above real-world results, and that gap widens in city traffic.
The honest way to get your real number is to measure it: fill the tank completely, reset the trip meter, drive normally until the tank is low, fill completely again, and divide the kilometres travelled by the litres it took to refill. Do it twice for confidence. Most people find their actual figure is several kilometres per litre below the brochure.
Your mileage also is not one number. Expect it to vary by roughly:
- City driving: often 20–30% below highway figures, because of idling, stop-start and low gears
- Air conditioning: typically 5–10% worse
- Load: a fully loaded car with roof luggage can lose 10–20%
- Speed: efficiency generally peaks somewhere around 60–80 km/h and falls off notably above 100
- Tyre pressure: under-inflation of 25% can cost 3–5%
For a mixed trip, using your honest city figure gives a conservative estimate and using the highway figure gives an optimistic one.
Common mistakes
Using the brochure mileage. ARAI and WLTP figures are test-cycle results, not predictions. Measure your own.
Forgetting the return journey. A 300 km destination is a 600 km round trip.
Ignoring tolls. On a long highway run, tolls can approach half the fuel cost.
Comparing per-car cost against per-person fares. Divide by the number of passengers before concluding that driving is cheaper than the train.
Assuming a CNG or EV saves the full difference in running cost. The per-kilometre cost is genuinely much lower, but the conversion or purchase premium, reduced boot space in CNG cars, and charging or refuelling availability all belong in the comparison.
Treating fuel as the cost of driving. It is roughly half of a car's true per-kilometre running cost once maintenance, tyres, insurance and depreciation are counted.
Not adjusting for price changes. Fuel prices in India move frequently and vary by state because of differing VAT rates. Enter today's local price rather than what you remember paying. ## Improving the number rather than just measuring it
Once you know your real cost per kilometre, several changes move it measurably, and they are worth ranking by effort against return.
Tyre pressure is the cheapest gain available. Checking monthly and keeping to the manufacturer's recommended figure — printed on the driver's door sill, not the tyre wall, which shows a maximum rather than a recommendation — typically recovers 3–5% on a car that has drifted under-inflated.
Removing weight and drag. A roof box or carrier left mounted between trips can cost 10–20% on the highway through aerodynamic drag alone, even empty. Unused weight in the boot matters less but is not nothing.
Steady speeds. Efficiency generally peaks somewhere around 60–80 km/h. Cruising at 110 rather than 90 can cost 15–20%, and on a long drive the time saved is usually smaller than drivers expect once traffic and stops are counted.
Anticipating rather than braking. Every braking event converts fuel you already burned into heat. Reading traffic far enough ahead to lift off early is the single largest behavioural factor in city consumption.
Avoiding long idling. More than a minute or so stationary uses more fuel than restarting. Modern engines, and anything with auto start-stop, handle frequent restarts without meaningful wear.
Servicing on schedule. A clogged air filter, degraded spark plugs or the wrong engine oil grade each cost a few percent, and they compound quietly because the decline is gradual enough not to be noticed.
Taken together these routinely recover 10–15% on a car that has been neglected — which on the 15,000 km example is ₹10,000–₹15,000 a year for no capital outlay at all.