Free tool
Fuel economy calculator (MPG and L/100 km)
Fuel economy is the distance driven divided by the fuel used, or the fuel used per 100 km. Enter the distance and the fuel you added at the pump and the tool shows L/100 km, MPG (US), MPG (imperial) and km/L, with a converter between the four.
Fill-to-fill method: fill the tank to full and reset the trip meter, drive normally, then fill to full again. Enter the trip distance and the fuel added at the second fill.
Your fuel economy
Enter the distance driven and the fuel used to see your fuel economy.
Convert fuel economy
Why measure fuel economy yourself
Your own measured fuel economy is the only figure that reflects how your vehicles are loaded, driven and maintained. Measured the same way every time, it shows when a vehicle starts using more fuel, which can point to a maintenance problem, a change in driving or more idling. It is also the number to use when you price trips and budget for fuel, because rated figures come from standard test cycles, not from your routes.
Fuel economy for every vehicle, without the arithmetic
Working this out by hand at every fill is slow, and receipts go missing. High Point GPS fleet tracking records each vehicle's trips, distance, idle time and fuel use from engine data, and presents it in fuel and idle reports. You can compare vehicles side by side and see which ones use more fuel than the rest of the fleet.
Get a quoteTips for a reliable number
Fill to full at the same pump if you can, and let it click off on its own both times, so the two fills are comparable.
Measure over several fills, not one. A single tank can be skewed by one long idle, a heavy load or a cold week.
Lower L/100 km is better; higher MPG is better. The two scales run in opposite directions, so compare like with like.
US and imperial gallons are different sizes, so MPG (US) and MPG (imperial) differ for the same vehicle. Check which one a figure uses.
Fuel economy questions
- How do I calculate my gas mileage?
- Fill the tank to full and reset the trip meter. Drive normally, then fill to full again and note the fuel added. Divide the distance by the fuel added for MPG or km/L, or divide the litres by the kilometres and multiply by 100 for L/100 km. This calculator does it for you.
- How do I convert L/100 km to MPG?
- Divide 235.215 by the L/100 km figure for MPG (US), or 282.481 for MPG (imperial). Both constants follow from the exact definitions: one mile is 1.609344 km, one US gallon is 3.785411784 litres and one imperial gallon is 4.54609 litres. The converter above does the sum both ways.
- Why are US and imperial MPG different?
- The gallons are different sizes. A US gallon is exactly 3.785411784 litres and an imperial gallon is exactly 4.54609 litres, so the same vehicle travels further on an imperial gallon and shows a higher MPG. Always check which gallon a figure uses before you compare two vehicles.
- Is a lower L/100 km figure better?
- Yes. L/100 km measures how much fuel the vehicle uses to cover 100 kilometres, so a lower number means less fuel. MPG and km/L work the other way round: they measure distance per unit of fuel, so a higher number is better. Mixing the two up is a common source of wrong comparisons.
- Why is my fuel economy worse than the sticker figure?
- A published figure is not measured on your roads, with your loads or your drivers. Loads, idling, short trips, cold weather, speed, hills, tire pressure and maintenance all change real consumption. Measuring your own vehicles over several fills, or reading the fuel reports from fleet tracking, gives the figure that matches your work.