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Gas Cost Calculator

Enter the trip distance, your vehicle’s fuel economy and the price of fuel to see how much fuel the drive will use and what it will cost. Switch on round trip to double the distance, and enter the number of people to split the bill.

Quick examples
mpg
$

Per gallon in the US setting; per liter in the UK and metric settings.

Your numbers stay in your browser. Nothing is uploaded.
Fuel cost$37.50
Fuel used
10.71 gal
Cost per person
$37.50
Distance driven
300 mi
Cost per mile
$0.13
Cost per kilometer
$0.08

Saved setups

Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.

    Your recent calculations

    Results you calculate here are kept on this device so you can come back to them.

      Formula

      US: gallons = miles ÷ mpg; cost = gallons × price per gallon
      Metric: liters = km × (L/100 km) ÷ 100; cost = liters × price per liter
      UK: liters = miles ÷ mpg × 4.546; cost = liters × price per litre
      Cost per person = cost ÷ people

      How to use it

      1. Choose the unit system that matches how you know your fuel economy and fuel price.
      2. Enter the one-way distance and tick round trip if you are coming back.
      3. Enter your fuel economy and the current fuel price.
      4. Enter how many people are sharing the cost.

      Worked examples

      A 300 mile drive at 28 mpg with gas at $3.50 a gallon

      Fuel used
      10.71 gal
      Fuel cost
      $37.50
      Cost per person
      $37.50
      Cost per mile
      $0.13

      A round trip of 120 miles each way at 30 mpg and $4 a gallon, split four ways

      Distance driven
      240 mi
      Fuel used
      8 gal
      Fuel cost
      $32.00
      Cost per person
      $8.00

      500 km at 7 L/100 km with fuel at 1.80 per liter

      Fuel used
      9.25 gal
      Fuel cost
      $63.00
      Cost per kilometer
      $0.13

      200 miles in a UK car doing 45 mpg with petrol at 1.45 a litre

      Fuel used
      5.34 gal
      Fuel cost
      $29.30

      Getting a realistic figure

      Use the fuel economy you actually get, not the window-sticker number. Highway driving at 75–80 mph, a roof box, a loaded car, mountain roads or towing can cut mpg by 10–30%. If most of the trip is highway, the EPA highway rating is a fair starting point.

      Fuel is only part of the cost of a drive. Tires, maintenance and depreciation add roughly as much again per mile; use the cost per mile calculator when you want the full figure.

      US and UK gallons are different

      An imperial gallon is 4.546 liters and a US gallon is 3.785 liters, so the same car shows about 20% higher mpg in the UK. UK fuel is priced per litre even though economy is quoted in miles per gallon, which is why the UK setting asks for a per-litre price.

      Questions people ask

      How much does it cost to drive 300 miles?

      At 28 mpg and $3.50 a gallon, 300 miles uses 10.7 gallons and costs $37.50. At 20 mpg it is $52.50, and at 40 mpg it is $26.25.

      How do I calculate gas cost for a trip?

      Divide the distance by your miles per gallon to get gallons, then multiply by the price per gallon. 240 miles ÷ 30 mpg = 8 gallons; 8 × $4 = $32.

      How should we split gas money fairly?

      Divide the total fuel cost by everyone in the car, driver included. Some groups leave the driver out or add a little for wear on the car, which runs around 10 cents a mile.

      Related calculators

      MPG CalculatorMiles per gallon from the distance driven and fuel used.Cost Per Mile CalculatorThe true cost of driving per mile: fuel plus ownership costs.Trip Time CalculatorDriving time and arrival time from distance, speed and stops.Commute Cost CalculatorWhat driving to work costs per day, month and year.Fuel Consumption ConverterConvert between US mpg, UK mpg, L/100 km and km/L.Bill Split CalculatorSplit a bill evenly with tip, and round shares up if you like.