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Fuel Cost Calculator

Estimate how much fuel a trip needs and what it will cost, in miles and MPG or kilometers and L/100 km, with optional round trip and cost sharing between passengers.

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Units

Results are estimates. Real fuel use depends on speed, traffic, load, terrain and weather.

How to use the fuel cost calculator

Choose US (miles, miles per gallon, price per gallon) or Metric (kilometers, liters per 100 km, price per liter). Then enter:

  • Trip distance one way
  • Fuel efficiency of your vehicle
  • Fuel price per gallon or per liter

Tick Round trip if you are coming back the same way, and enter the number of people if you want to split the cost. Press Calculate to see the fuel needed, the total cost, the cost per person and the cost per mile or kilometer.

How the cost is calculated

With US units, fuel efficiency is distance per unit of fuel:

  • Fuel needed (gallons) = distance (miles) / MPG

With metric units, consumption is fuel per distance:

  • Fuel needed (liters) = distance (km) × L/100 km / 100

In both cases, total cost = fuel needed × price, cost per person = total cost / people, and cost per mile or km = total cost / distance. A round trip doubles the distance. Money amounts are rounded to two decimals.

Worked example

A 300-mile drive in a car that gets 30 MPG, with fuel at 3.50 per gallon, needs 300 / 30 = 10 gallons and costs 10 × 3.50 = 35.00. As a round trip it is 600 miles, 20 gallons and 70.00, or 23.33 each for three people. That works out to about 0.12 per mile.

In metric: 500 km at 6.5 L/100 km needs 500 × 6.5 / 100 = 32.5 liters. At 1.80 per liter the trip costs 58.50.

Good to know

  • The results are estimates. Real consumption changes with speed, traffic, air conditioning, load, tire pressure, hills and weather.
  • Use your own measured fuel economy if you can. Official ratings are often optimistic for highway driving at high speed.
  • MPG here means US miles per US gallon. If your figure is in UK MPG (imperial gallons), convert it first or use the metric option.
  • The calculator uses no currency symbol, so it works with any currency.
  • Tolls, parking and vehicle wear are not included.

Frequently asked questions

How do I calculate fuel cost for a trip?

Work out how much fuel you need (miles divided by MPG, or km times L/100 km divided by 100), then multiply by the price per gallon or liter. This calculator does both steps and can double the distance for a round trip.

How do I convert MPG to L/100 km?

Divide 235.215 by the US MPG figure. For example, 30 MPG is about 7.84 L/100 km. The relationship is inverse, so a higher MPG means a lower L/100 km.

Why is my actual fuel cost different?

Fuel use depends on driving speed, traffic, terrain, load, weather and the condition of the vehicle, and fuel prices vary along the way. Treat the result as an estimate for planning and budgeting.

How is the cost split between passengers?

The total fuel cost is divided equally by the number of people you enter, and each share is rounded to cents. Because of rounding, the shares can differ from the total by a cent.