Fuel Efficiency Calculator | MPG, km/L and L/100km
Calculate fuel consumption from distance driven and fuel used, then compare MPG, kilometers per liter, and liters per 100 km.
Calculate Fuel Economy from Distance and Fuel Used
Enter distance driven and fuel consumed to calculate liters per 100 km, kilometers per liter, and US miles per gallon for a trip or tank.
Use Real Fill-Up Data for Accuracy
Fuel economy changes with traffic, tire pressure, driving style, load, weather, route, and measurement method. Full-tank records are usually more reliable than guesses.
When Fuel Efficiency Math Helps
Use it for comparing vehicles, checking trip costs, monitoring fuel changes after maintenance, planning routes, or translating fuel economy between metric and MPG formats.
About This Tool
Fuel Efficiency Calculator converts between miles per gallon, litres per 100 km, and kilometres per litre. It also computes real efficiency from a known distance and fuel used, so you can track your vehicle's actual consumption after each fill-up.
When to Use It
Use this when comparing vehicle specifications listed in different units, when calculating actual fuel efficiency after a tank fill-up, or when converting an overseas vehicle's rating to your local unit.
How to Use
- Select convert units or calculate from actual data.
- Enter the distance and fuel quantity used, or the value to convert.
- Click Calculate to see the result in all units.
Frequently Asked Questions
What is considered good fuel efficiency?
Under 6 litres per 100 km (above 47 UK mpg) is economical for a petrol car. Hybrids and modern diesels can achieve 4 to 5 litres per 100 km in real-world conditions.
Why is real-world efficiency lower than the manufacturer figure?
Official figures are measured under controlled test conditions. Real driving includes acceleration, air conditioning, and varying speeds that increase consumption.
Can I use this for a motorcycle?
Yes. Enter the distance and fuel quantity for any petrol-powered vehicle to calculate its efficiency.