What Is the Fuel Mileage Calculator?
The Fuel Mileage Calculator tells you how efficiently your vehicle uses fuel by computing miles per gallon (MPG). Simply divide the distance you traveled by the amount of fuel you used. Higher MPG means better fuel economy and lower running costs. This tool also converts your result into liters per 100 kilometers (L/100 km), the metric standard used in much of the world.
How to Use It
Enter the distance you traveled (in miles) since your last fill-up, and the amount of fuel you used (in gallons) to cover that distance. The easiest method is to fill your tank, reset the trip odometer, drive normally, then refill — the gallons it takes to top off equals the fuel used, and the trip odometer gives the distance. Click calculate to see your MPG instantly.
The Formula Explained
The core equation is $$\text{MPG} = \frac{\text{Distance (miles)}}{\text{Fuel (gallons)}}$$. If you drove 300 miles and used 12 gallons, your mileage is \(300 / 12 = 25\) MPG. To convert to metric, divide the constant 235.215 by your MPG: \(235.215 / 25 \approx 9.41\) L/100 km. The constant accounts for the conversion between US gallons, liters, miles, and kilometers.
Worked Example
Suppose you filled up, drove 420 miles, and then needed 14 gallons to refill the tank. Your fuel mileage is \(420 / 14 = 30\) MPG, equivalent to \(235.215 / 30 \approx 7.84\) L/100 km — solid efficiency for a sedan.
FAQ
Does this use US or Imperial gallons? The calculation works for any gallon, but the L/100 km conversion uses the US gallon constant (235.215). For Imperial gallons use 282.481.
What is a good MPG? Compact cars often achieve 30–40 MPG, while large trucks and SUVs may be 15–20 MPG. Hybrids can exceed 50 MPG.
How can I improve my mileage? Keep tires properly inflated, avoid hard acceleration, reduce idling, and remove excess weight from the vehicle.
