Fuel Cost Calculator

How to Use

Pick your unit system, then enter the trip distance, your vehicle's efficiency (MPG for US, L/100km for metric), and the current fuel price. The total fuel cost appears as the headline figure, with the amount of fuel needed and the cost per mile or kilometre below.

Why This Tool Is Useful

Fuel is often the biggest variable cost of a trip, but people rarely work it out before setting off. Whether you're budgeting a road trip, comparing routes, deciding whether to drive or fly, or splitting costs with passengers, knowing the real fuel cost helps. This calculator handles the unit conversions and gives you a clear per-trip and per-mile figure in seconds.

MPG vs L/100km

The US measures fuel economy as miles per gallon (higher is better). Most of the world uses litres per 100 kilometres (lower is better) — it's the amount of fuel to go a fixed distance. The two are inversely related, which is why this tool lets you pick the system that matches your car's rating so you don't have to convert.

How the Cost Is Worked Out

In US units, fuel used = distance ÷ MPG (in gallons), then cost = gallons × price per gallon. In metric, fuel used = distance ÷ 100 × L/100km (in litres), then cost = litres × price per litre. The cost-per-distance figure simply divides the total cost by the trip distance.

Getting an Accurate Estimate

Real-world economy is usually a bit worse than the sticker rating, especially in city driving, cold weather, or with a loaded vehicle or roof rack. For a safety margin, use your car's real observed economy if you know it, and round fuel price up. Highway trips at steady speeds tend to match or beat the rated figure.

MPG to L/100km (US gallon)