Trip fuel formula
Metric: litres used = distance × (L/100 km) ÷ 100. Cost = litres × price per litre. US: gallons used = miles ÷ MPG. Cost = gallons × price per gallon. Real trips vary with speed, heat, cargo, and winter fuel.
Worked example
A 400 km trip at 8.0 L/100 km uses 32 litres. At $1.55/L that is $49.60. The same trip at 28 MPG over 250 miles uses about 8.93 gallons; at $3.80/gal that is about $34.
Highway ratings assume steady speed. Winter fuel, a roof box, and city traffic can add 10–20%. Carry a reserve on long gaps between stations in the North or on the Prairies.
Common questions
Where do I find L/100 km?
On the window sticker, your trip computer, or the Natural Resources Canada fuel rating for the model.
Should I add a buffer?
Yes. 10–15% extra is reasonable for hills, traffic, and a reserve.