This trips people up when switching between US and metric sources: MPG is distance per unit of fuel — bigger is better. L/100km is fuel per unit of distance — smaller is better. They're inverses of each other, not just different units on the same scale. On the calculator's own defaults, 300 miles at 28 MPG and $3.50/gallon costs $37.50 in fuel (12.5 cents per mile); 500 km at 7.5 L/100km and $1.60/liter costs $60.00 (12 cents per km). Both examples land close to the same cost-per-distance despite one tab reporting a "bigger is better" number and the other reporting a "smaller is better" one — worth remembering before assuming a European car's "7.5" is automatically worse than an American car's "28" without converting.
A single tank rarely makes fuel efficiency feel urgent, but it compounds fast over a full year of typical driving. Using 12,000 miles a year at $3.50/gallon as a baseline:
| Fuel efficiency | Annual fuel cost |
|---|---|
| 22 MPG | $1,909.09 |
| 28 MPG | $1,500.00 |
| 35 MPG | $1,200.00 |
Going from 22 to 35 MPG saves over $700 a year on this example — real money that a single trip's cost estimate doesn't make obvious. It's worth running your actual annual mileage through the calculator once for a full-year figure, not just a single trip, if fuel cost is part of a bigger decision like comparing two vehicles.
Use your vehicle's official rating for a rough estimate, or your own calculated average for better accuracy — real-world fuel economy varies with driving style, terrain, and conditions.
MPG (miles per gallon) is standard in the US, while L/100km is standard in most of the rest of the world — pick whichever matches how your vehicle reports efficiency.
No — this estimates fuel cost only, based on distance, efficiency, and fuel price.