Fuel Cost Calculator

Estimate the fuel cost of a trip from distance, economy and price.

mi
mpg
$
Total fuel cost
$0
Fuel needed
0
Cost per mile
$0
Distance
0
Cost per 100
$0

Estimate only. Real consumption varies with speed, load, terrain, traffic and driving style.

How the estimate works

In US units, the fuel used is the distance divided by miles-per-gallon, multiplied by the price per gallon. In metric units, economy is expressed as litres per 100 km, so the fuel used is distance ÷ 100 × L/100km, multiplied by the price per litre.

USCost = (distance ÷ mpg) × price per gallon
MetricCost = (distance ÷ 100 × L/100km) × price per litre

A lower L/100km figure is more efficient, whereas a higher mpg is more efficient — the two scales run in opposite directions.

Worked example

A 300-mile trip in a car doing 30 mpg uses 10 gallons of fuel. At $3.50 a gallon that is $35 for the trip, or about 11.7 cents per mile.

What actually drives the cost of a trip

Three things set your fuel bill: how far you travel, how efficiently your vehicle uses fuel, and the price at the pump. Of these, efficiency is the one you can influence day to day — and real-world economy is often well below the official figure.

Stretch each tank further

  • Ease off. Smooth, moderate speeds use far less fuel than hard acceleration and high motorway speeds.
  • Lighten the load. Extra weight and roof racks raise consumption.
  • Keep tyres inflated. Under-inflation quietly costs both fuel and tyre life.
  • Combine errands. A warm engine is more efficient, so one longer trip beats several cold starts.

Frequently asked questions

Is mpg or L/100km better?
They measure the same thing in opposite directions: a higher mpg is more efficient, while a lower L/100km is more efficient. Use whichever figure your car displays.
Why is my real economy different from the rating?
Speed, traffic, terrain, load, weather and driving style all affect consumption, so real-world figures often fall short of the official rated economy.
How do I budget for a round trip?
Switch on the round-trip option, which doubles the distance before working out the fuel needed and the total cost.
How can I cut my fuel costs?
Steady speeds, correct tyre pressure, less idling and removing excess weight all help. Combining errands into one trip also reduces cold-engine running, which is less efficient.