Gas Mileage Cost Calculator

About Gas Mileage Cost Calculator

Estimating what a road trip or daily commute actually costs in fuel means combining three numbers correctly — the distance, the vehicle's fuel efficiency, and the current fuel price — and the math changes depending on which efficiency unit you're working with. This tool supports all three common fuel efficiency conventions used around the world: miles per gallon (MPG, standard in the US), liters per 100 kilometers (L/100km, standard across most of Europe), and kilometers per liter (km/L, common in parts of Asia).

Each unit represents fuel efficiency in a fundamentally different way, which is why they aren't simply interchangeable with a basic conversion factor applied to the final cost. MPG and km/L both express distance per unit of fuel (higher is better), while L/100km expresses fuel per unit of distance (lower is better) — the calculation logic for each is genuinely different, not just a relabeling of the same formula.

Enter your trip distance, your vehicle's efficiency rating in whichever unit matches how it's listed (a US vehicle's window sticker, a European spec sheet, or a manufacturer's km/L rating), and the current fuel price, and this tool calculates both the amount of fuel the trip will require and the total cost.

This is useful for budgeting a road trip before you leave, comparing the true cost of two vehicles with different efficiency ratings and fuel types, or estimating a regular commute's fuel cost over a week or month by multiplying the per-trip result.

How it works

1. Choose your fuel efficiency unit. MPG, L/100km, or km/L, matching your vehicle's listed rating.
2. Enter distance, efficiency, and fuel price. Fields update their unit labels to match your selection.
3. View fuel needed and total cost. Both update instantly based on your inputs.