Fuel Cost Calculator
Estimate trip fuel cost, litres used, cost per mile or km, and compare multiple vehicles side by side. Supports L/100km, MPG (UK & US), and km/L.
Add up to 5 vehicles to compare fuel cost, litres used, and cost per km side by side.
Estimate your yearly spend on fuel based on annual mileage and efficiency.
How to maximise fuel efficiency
Avoid harsh acceleration and braking. Most vehicles reach peak fuel efficiency between 50–60 mph — maintaining a steady speed at this range reduces consumption significantly.
Use air conditioning in moderation. It places extra load on the engine and can increase fuel use by 5–10%, particularly in city driving.
Shift up early to keep engine RPM low. Higher gears at moderate speeds reduce engine load and improve economy — aim to shift before 2,500 RPM in petrol cars.
Keep tyres inflated to the manufacturer's recommended pressure. Under-inflated tyres increase rolling resistance, which forces the engine to work harder and burns more fuel.
Keep up with regular servicing — fresh oil, clean air filters, and spark plugs in good condition all contribute to a more efficient engine.
Avoid idling for more than a minute or two. A modern engine uses less fuel restarting than idling for extended periods.
How it's calculated
All efficiency figures are converted to litres per 100 km internally before calculating fuel use.
- L/100km: Fuel (L) = distance (km) × efficiency ÷ 100
- MPG (UK): Converted using 1 UK gallon = 4.54609 L and 1 mile = 1.60934 km
- MPG (US): Converted using 1 US gallon = 3.78541 L and 1 mile = 1.60934 km
- km/L: Fuel (L) = distance (km) ÷ efficiency
Results are estimates only. Real-world fuel use varies with speed, traffic, load, temperature, tyre pressure, and driving style. Add a 5–10% buffer for a more conservative estimate.