Core formulas
Required fuel equals total distance divided by fuel economy. Fuel cost equals required fuel multiplied by price per liter. Apply the return-trip multiplier before calculating when the input is one-way distance.
For a shared car, divide the total by travelers to estimate an equal share.
- Fuel required = total distance ÷ real economy
- Fuel cost = fuel required × price per liter
A 200 km example
Driving 200 km at 12 km/L requires about 16.67 L. At 1.70 per liter, the estimated fuel cost is about 28.33 in the same currency scale.
Four equal shares are about 7.08 each, although a group may choose a different arrangement for the driver.
Why real economy matters
City traffic, highway share, weather, cargo, and driving style change actual economy. A recent dashboard average or fill-up record usually reduces error.
For planning, entering a slightly lower economy creates a useful buffer.
Costs outside fuel
Tolls, parking, washing, tires, maintenance, and depreciation are not part of basic fuel cost. Add them separately when comparing the full cost of transportation.
Fuel prices vary by location and discount, so use the price you expect to pay near departure.