🚗 Fuel Cost Calculator

How it works

This calculator answers a simple question: how much will the fuel cost for this trip? Give it the distance, your vehicle's fuel efficiency, and the current price of fuel, and it works out the litres (or gallons) you will burn and what they will cost. It is handy for budgeting road trips, comparing the running costs of two cars, or deciding whether driving beats flying.

It speaks both metric and imperial. Canadians usually think in litres per 100 km and dollars per litre, but if your vehicle is rated in miles per gallon, the calculator handles that too — just watch which gallon you mean (see below).

The formula

With metric figures: litres used = distance × (L/100 km ÷ 100), then cost = litres used × price per litre. With imperial figures: gallons used = miles ÷ MPG, then convert to litres if your pump price is per litre (1 US gallon = 3.785 L). Double the distance for a round trip.

Worked example

A 450 km trip in a car rated at 8.5 L/100 km, with fuel at $1.45 per litre: litres used = 450 × (8.5 ÷ 100) = 450 × 0.085 = 38.25 litres. Cost = 38.25 × $1.45 = $55.46. The same trip there and back costs about $110.93.

Frequently asked questions

What is the difference between a US gallon and an Imperial gallon?
A US gallon is 3.785 litres; an Imperial gallon is 4.546 litres — about 20% larger. A car rated 30 MPG (US) would be rated about 36 MPG (Imperial) for the exact same efficiency. Mixing them up wrecks the math.

Why does my real fuel use exceed the official rating?
Official ratings come from lab tests. Winter driving, short trips, idling, heavy loads, and roof boxes all push consumption higher — often 15–25% above the rating in cold Canadian winters.

What is my cost per 100 km?
Just multiply your L/100 km figure by the fuel price. At 8.5 L/100 km and $1.45/L, you are spending about $12.33 per 100 km.