Fuel Consumption Calculator - MPG, L/100km & km/L
Calculate fuel consumption from distance and fuel used, shown in MPG (US & UK), L/100km, and km/L simultaneously.
km/L
12.50
L/100km
8.00
US MPG
29.40
UK MPG
35.31
How to Calculate Fuel Consumption
Fuel consumption (or economy) compares distance traveled to fuel used, but it's expressed in different ways around the world: miles per gallon (US or UK) in the US and UK, liters per 100 km in most of Europe, and kilometers per liter in many parts of Asia and Latin America. This calculator converts your distance and fuel figures to a common base (kilometers and liters), then computes all four common units at once.
Example
A car that travels 400 km using 32 liters of fuel gets 400 ÷ 32 = 12.5 km/L, which is equivalent to (32 ÷ 400) × 100 = 8 L/100km, about 29.4 US mpg, and about 35.3 UK mpg (since a UK/imperial gallon holds more fuel than a US gallon).
Common Use Cases
- Comparing a car's advertised fuel economy figures across regions with different units.
- Tracking your own vehicle's real-world fuel economy from odometer and fuel receipts.
- Estimating trip fuel costs by combining consumption with fuel price and distance.
FAQs
Why is UK mpg higher than US mpg for the same car?
A US gallon (3.785 liters) is smaller than a UK/imperial gallon (4.546 liters). Since mpg is distance per gallon, using the larger UK gallon in the calculation produces a higher mpg number for the exact same real-world fuel economy.
Is a higher or lower L/100km number better?
Lower is better for L/100km, since it means less fuel is used to cover the same distance. This is the opposite of mpg or km/L, where a higher number means better fuel economy.
How accurate is my own calculated fuel economy?
Real-world figures depend on driving style, terrain, load, and how precisely you measure the fuel added at each fill-up. Averaging results over several tanks of fuel gives a more reliable figure than a single measurement.