Free · Everyday calculations

Trip Fuel Use & Cost Calculator

Calculate fuel economy, consumption and fuel spending for a trip.

  • Formula & worked example
  • Private in your browser
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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. Edit a calculated value to solve backwards, or 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

Divide distance by fuel used for fuel economy, or divide fuel used by distance and multiply by 100 for liters per 100 kilometers. Traveling 500 kilometers on 50 liters gives 10 km/L and 10 L/100 km; at 1.50 per liter, the fuel costs 75.

Economy = distance ÷ fuel; consumption = fuel ÷ distance × 100; cost = fuel × price

Worked example

Enter these known values and leave the other values blank.

Distance traveled
500 km
Fuel used
50 L
Fuel price
1.5 USD / L
Fuel economy
10 km/L
Fuel consumption
10 L/100 km
Trip cost
75 USD

Assumptions and limitations

  • L/100 km measures fuel needed for a fixed distance, so less is better. Distance-per-fuel measures such as km/L work in the opposite direction. Traffic, weather and driving conditions can change actual consumption.
  • Use the units shown beside each field. This model assumes the stated relationship and does not account for quantities left out of the formula.

Common questions

Why does a lower L/100 km mean better efficiency?

L/100 km measures fuel needed for a fixed distance, so less is better. Distance-per-fuel measures such as km/L work in the opposite direction. Traffic, weather and driving conditions can change actual consumption.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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