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Fuel Cost Calculator

Estimate the fuel cost of a drive from distance, mileage and your fuel price, with round trips, cost per km and a split.

By Nitin Raturi · Last reviewed

Your trip

How to use the Fuel Cost Calculator

Estimate the fuel cost of a drive from distance, mileage and the price you pay per litre.

  1. Enter the one-way distance in kilometres.
  2. Pick the unit your mileage is written in, then enter the mileage.
  3. Enter the fuel price per litre you actually pay.
  4. Choose one way or round trip, and how many people share the cost.
  5. Read the total cost, litres needed, cost per km and cost per person.

Good to know

  • Your own refill records usually give a more realistic mileage than the brochure.
  • Tap the ⓘ next to any field for a short guide to it.

Enter the price you pay; this tool does not fetch live fuel prices. Inputs stay in your browser.

Distance (one way)

How far you will drive to reach the destination, in kilometres.

How to fill it in

  • Enter kilometres, for example 300 or 42.5. Commas are fine.
  • Allowed range: 0.1 km to 1,00,000 km. Choose “Round trip” below to double it.

Example

300 km at 15 km/l needs 20.00 litres.

Tip: A map app’s route distance is closer to what you drive than a straight-line distance.

Mileage unit

Mileage unit

How your mileage figure is written. Indian cars usually quote km/l; some countries use l/100 km or miles per gallon.

How to fill it in

  • km/l: kilometres per litre. l/100 km: litres used per 100 km, so lower is better.
  • mpg (US) and mpg (UK) use different gallons; the UK gallon is larger.

Example

15 km/l is 6.67 l/100 km, 35.28 mpg (US) or 42.37 mpg (UK).

Keep in mind: Switching the unit only changes how the figure is shown. The trip cost stays the same.

Mileage

How far the vehicle goes on fuel, in the unit you chose above.

How to fill it in

  • Use your own measured figure if you have one: kilometres driven ÷ litres refilled.
  • Allowed range: 0.5 to 200 km/l, or the same span in the other units.

Example

At 15 km/l and ₹100.00 a litre, each km costs ₹6.67.

Keep in mind: Brochure or test-cycle mileage is often higher than real driving in traffic, on hills or with the AC on.

Fuel price per litre

What you pay for one litre of petrol or diesel. This tool does not look up live prices.

How to fill it in

  • Enter rupees per litre from your pump receipt or your fuel company’s price page.
  • Allowed range: ₹0.01 to ₹10,000. Prices differ between cities and change often.

Example

The default ₹100.00 is only an example and gives a trip cost of ₹2,000.00.

Keep in mind: Use a price for the fuel your vehicle takes. CNG (sold per kg) and charging (per kWh) are not covered.

Trip

Trip

Whether you drive one way or there and back.

How to fill it in

  • One way uses the distance as entered.
  • Round trip doubles the distance.

Example

A round trip of 600 km costs ₹4,000.00.

People sharing the cost

How many people split the fuel bill equally.

How to fill it in

  • Enter a whole number from 1 to 100.
  • Use 1 if you are paying alone.

Example

4 people sharing a ₹4,000.00 round trip pay ₹1,000.00 each.

Tip: Tolls and parking are not included; add them separately before splitting.

Fuel cost for this trip

₹2,000.00

20.00 litres for 300 km at ₹100.00 a litre.

Fuel needed
20.00 litres
Distance driven
300 km
Cost per km
₹6.67
Cost per person
₹2,000.00
Mileage used
15 km/l = 6.67 l/100 km

Assumes your mileage and price hold for the whole trip. Excludes tolls, parking, servicing, wear and fuel used while idling. Rupees are rounded to paise for display only.

ChangelogHow we test this calculatorEmbed this calculator

How this calculator works

  1. Step 1Distance300 kmOne way; a round trip doubles it.
  2. Step 2Fuel needed20.00 litresDistance ÷ 15 km/l.
  3. Step 3Fuel cost₹2,000.00Litres × ₹100.00 a litre.

The calculator divides the distance by the mileage to get litres, then multiplies by the price you pay per litre. Cost per km is the price divided by the mileage. Splitting divides the total equally between the people sharing it.

All three figures are your own inputs. The page does not fetch live fuel prices, because they differ between cities and change often. The default price is only an example.

Worked example: a shared round trip

300 km each way, 4 people
Distance driven
one-way km × 2 for a round trip
Fuel needed
distance ÷ km per litre
Cost
litres × price per litre
Each person
cost ÷ people
  • kmDistance one way 300 km
  • km/lMileage 15 km/l
  • ₹/lExample fuel price ₹100.00
  1. Distance driven300 km × 2600 km
  2. Fuel needed600 km ÷ 15 km/l40.00 litres
  3. Fuel cost40.00 litres × ₹100.00₹4,000.00
  4. Cost per km₹100.00 ÷ 15 km/l₹6.67
  5. Each of 4 people pays₹4,000.00 ÷ 4₹1,000.00

Cost per km does not depend on distance. It stays ₹6.67 whether the trip is one way or there and back. Only the total and each share change.

How mileage changes the bill

  • 10 km/l₹3,000.00
  • 15 km/l₹2,000.00
  • 20 km/l₹1,500.00
Fuel cost of 300 km at ₹100.00 a litre

Cost falls as mileage rises, but not in a straight line. The first step up in mileage saves more than the second on the same trip, because fuel needed is distance divided by mileage.

Mileage units: km/l, l/100 km and mpg

  • Kilometres per litre15 km/lCommon in India. Higher is better.
  • Litres per 100 km6.67 l/100 km100 ÷ km/l. Lower is better.
  • Miles per gallon35.28 US / 42.37 UKThe UK gallon is larger than the US one.

The conversions use exact definitions: a mile is 1.609344 km, a US gallon is 231 cubic inches (about 3.785 litres) and a UK gallon is 4.54609 litres.

NIST’s own conversion example, 20 US mpg, converts to 8.503 km/l or 11.76 l/100 km.

Switching units changes only how your mileage is shown. The value used for the cost is kept at full precision, so switching back and forth never changes the result.

Reading the result

Treat the total as a fuel-only estimate for the mileage and price you entered.

Fuel cost is the headline total. Fuel needed helps you plan refills. Cost per km lets you compare vehicles or routes. Cost per person is the equal split of the fuel bill only.

Real trips vary. Traffic, hills, speed, load, tyre pressure and air conditioning all change mileage. Tolls, parking and servicing are extra, and are not part of this figure.

Fuel cost depends on mileage, distance and price. Each can be worked out on its own.

To find your car’s real mileage from a fill-up, use the gas mileage calculator. For travel time at an average speed, try the speed calculator.

Common mistakes

  • Mistake: Use the brochure mileage for city driving.

    Instead: Use your own figure: km driven between fills ÷ litres refilled.

  • Mistake: Enter the one-way distance and forget the drive back.

    Instead: Choose “Round trip” so the distance is doubled.

  • Mistake: Mix up US and UK miles per gallon.

    Instead: Pick the mpg unit that matches where the figure came from.

  • Mistake: Split the total and forget tolls and parking.

    Instead: Add those costs separately before sharing the bill.

Checking the method

Every golden value is recomputed by a separate script using exact fractions.

A Python script recomputes each test case with exact fractions, following each unit’s own route. Miles-per-gallon cases convert kilometres to miles and gallons to litres, rather than km per litre. It also reproduces the NIST worked example above.

Read how we test our calculators, or browse more everyday tools.

Frequently asked questions

How do I calculate the fuel cost of a trip?

Divide the distance by the mileage to get litres, then multiply by the price per litre. 300 km at 15 km/l needs 20.00 litres; at ₹100.00 a litre that is ₹2,000.00.

How do I work out fuel cost per km?

Divide the price per litre by the km per litre. At ₹100.00 a litre and 15 km/l, each km costs ₹6.67, whatever the distance.

Does this calculator use today’s petrol or diesel price?

No. Enter the price you pay. Fuel prices differ between cities and change often, so the tool does not store or fetch them. The default price is only an example.

How do I split fuel cost between friends?

Choose round trip if you are coming back, then enter how many people share. A 600 km round trip costing ₹4,000.00 is ₹1,000.00 each for 4 people. Tolls and parking are extra.

How do I convert km/l to l/100 km or mpg?

l/100 km is 100 divided by km/l. 15 km/l is 6.67 l/100 km, 35.28 mpg (US) or 42.37 mpg (UK). NIST gives 20 US mpg as about 8.503 km/l.

Why is my real fuel cost higher than the estimate?

Brochure mileage is measured in standard tests and is often higher than real driving. Traffic, hills, speed, load and air conditioning use more fuel. A tank-to-tank figure from your own refills is usually closer.

Can I use it for CNG or an electric car?

Not directly. CNG is sold per kilogram and charging per kWh, while this tool works in litres. The same idea applies: distance ÷ efficiency × price per unit.

Sources and methodology

The formulas are standard time-value-of-money results. We check every figure against golden values worked out independently, by closed form and by month-by-month simulation; see the methodology.

Written and maintained by Nitin Raturi, a software engineer (about the author). Last reviewed 3 Nov 2026; next review due by . Found an error? Tell us.

Changelog

  • : Initial release.

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