Free · Transportation calculators 🚘

Trip Fuel Cost & Return Journey Estimate

Estimate fuel quantity and entered-price cost for a one-way or return trip, using known consumption or measured distance and fuel.

  • Formula & worked example
  • Private in your browser
  • No signup
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

At 5 litres per 100 km, a 100 km one-way trip uses 5 litres. At 2 per litre it costs 10; an equal-distance return journey doubles both estimates.

Fuel volume = total trip distance ÷ distance per fuel unit; cost = fuel volume × price per fuel unit

Worked example

Enter these known values and leave the other values blank.

One-way distance
100 km
Average fuel economy or consumption
5 L/100 km
Entered price per fuel unit
2 USD / L
Estimated fuel cost
10 USD
Estimated trip fuel volume
5 L

Assumptions and limitations

  • Average consumption and price remain constant over the trip. Idling, traffic, terrain and changing prices can make actual use differ.
  • The return option doubles the entered one-way distance. Do not enter the full return distance and also select that option.
  • Measured fuel and measured distance must both be positive. Trip distance and entered price may be zero.
  • US and UK gallons are different units. Use the appropriate gallon in both economy and price selectors.

Common questions

How is fuel economy measured here?

Enter a positive measured distance and the fuel used over that distance. Their ratio supplies the economy used for the trip.

Does the tool obtain a current fuel price?

No. Enter the price you want to use, with its matching volume unit.

References

Bookify includes zero trip distance or price and requires positive distance and volume for measured fuel economy. Bookify replaces the captured rounded US gallon with the exact 3.785411784-liter definition. US MPG uses the same exact US gallon as volume and price inputs.

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