Free Fuel Cost Calculator Online
Estimate how much fuel your trip will cost. Enter distance, your vehicle's fuel efficiency and the current fuel price to get an instant cost estimate.
About the Fuel Cost Calculator
This free fuel cost calculator helps you estimate the total petrol or diesel expense for any trip. Simply enter your trip distance, your vehicle's fuel efficiency (km/L or MPG), and the current pump price, and the calculator instantly tells you how many litres (or gallons) you will need and the exact cost.
It is useful for road-trip budgeting, comparing vehicles before a purchase, or tracking monthly fuel expenses. Both metric (kilometres and litres) and imperial (miles and US gallons) unit systems are fully supported. Your inputs are auto-saved so they are ready next time you visit.
How to Calculate Fuel Cost
Select Unit System
Choose Metric (km/L) or Imperial (miles/gallon) depending on your preference.
Enter Distance
Type the one-way or total trip distance in kilometres or miles.
Enter Fuel Efficiency
Enter your car's fuel efficiency — check your vehicle manual or previous fuel-ups for an accurate figure.
Enter Fuel Price
Enter the current pump price per litre or gallon and click Calculate.
Key Features
Metric & Imperial
Supports km/L and miles per US gallon seamlessly.
Auto-Save
Distance, efficiency and price are remembered for your next visit.
100% Private
All calculation is browser-based. Nothing is sent to any server.
Instant Results
Fuel needed, total cost and cost per distance unit shown instantly.
Frequently Asked Questions
Fuel needed (L) = Distance (km) ÷ Efficiency (km/L). Total cost = Fuel needed × Price per litre. Cost per km = Total cost ÷ Distance.
Fill your tank completely, reset the odometer, drive normally until you need to refuel, then note the kilometres driven and litres used. Efficiency = km driven ÷ litres used.
The imperial mode uses US gallons (1 US gallon = 3.785 L). UK (imperial) gallons are slightly larger (1 UK gallon = 4.546 L) — if you use MPG (UK), convert your MPG figure accordingly.
Yes — simply double your one-way distance before entering it, or multiply the result by 2 after calculating.