Mitsubishi ECLIPSE Owner's Manual page 495

How to calculate your gasoline mileage
You can calculate your miles-per-gallon or kilometers-per-litre
by using the following process:
1. Fill your vehicle's fuel tank and record the odometer mile-
age.
2. Drive your vehicle as you normally do.
Gas mileage record
Gallons
Date Odometer /Litres
This Fill
Miles Per Gallon/Kilo-
Cost Per
meters Per Litre
Cost
Gallon
This Fill
(Miles/Gals.)/(Kilome-
/Litre
ters/Litres)
3. Refill the fuel tank. Record the odometer mileage again,
as well as the gallons/litres of fuel used.
4. Subtract the first mileage number from the second number
to know how many miles/kilometers were driven. Divide
the number of miles/kilometers driven by the number of
gallons/litres of fuel used. This is your approximate miles-
per-gallon or kilometers-per-litre.
Gas mileage record
Gallons
Date Odometer /Litres
This Fill
Miles Per Gallon/Kilo-
Cost Per
meters Per Litre
Cost
Gallon
This Fill
(Miles/Gals.)/(Kilome-
/Litre
ters/Litres)