A Gallons Per Mile Calculator helps you understand your vehicle's fuel efficiency from a different perspective. While most people are familiar with miles per gallon (MPG), which tells you the distance a car can travel on one gallon of fuel, this calculator does the opposite. It calculates how many gallons of fuel your vehicle consumes to travel a single mile. This measurement, known as gallons per mile (GPM), provides a direct measure of fuel consumption, which can be very useful for comparing the efficiency of different vehicles and understanding your fuel costs. This calculator is part of the automotive and fuel efficiency category.
formula
The calculation for gallons per mile is straightforward. You can find your vehicle's GPM by using the following formula.
Gallons per Mile = Gallons of Fuel Used / Miles Traveled
Miles Per Gallon (MPG) to Gallons Per Mile (GPM) Conversion Table
To make it easier to understand your vehicle's fuel consumption in GPM, you can convert its MPG rating. A lower GPM figure indicates better fuel efficiency. This table provides quick conversions for common MPG values.
| Miles Per Gallon (MPG) | Gallons Per Mile (GPM) |
| 10 | 0.1000 |
| 15 | 0.0667 |
| 20 | 0.0500 |
| 25 | 0.0400 |
| 30 | 0.0333 |
| 35 | 0.0286 |
| 40 | 0.0250 |
| 45 | 0.0222 |
| 50 | 0.0200 |
| 55 | 0.0182 |
| 60 | 0.0167 |
Example
Let's look at a practical example to understand how to use the gallons per mile formula.
Imagine you just completed a trip and want to calculate your car's fuel consumption. To do this, you need two pieces of information: the total distance you drove and the total amount of fuel you used.
You can get these numbers easily. When you fill up your gas tank, reset your trip odometer to zero. Drive until you need to refuel. At the gas station, note the number of miles on your trip odometer. Then, fill the tank completely and record how many gallons of fuel you added.
For this example, let's say:
Miles Traveled = 250 miles
Gallons of Fuel Used = 10 gallons
Now, you apply the formula:
Gallons per Mile = Gallons of Fuel Used / Miles Traveled
Gallons per Mile = 10 / 250
Gallons per Mile = 0.04
This result means that your vehicle used 0.04 gallons of fuel for every single mile you drove.
Most Common FAQs
While MPG is a useful metric, GPM can offer a clearer picture of fuel savings. For example, improving a car's efficiency from 10 MPG to 20 MPG saves a significant amount of fuel. Over 100 miles, you would save 5 gallons. However, improving efficiency from 40 MPG to 50 MPG saves only 0.5 gallons over the same distance. The GPM metric shows this difference more directly, making it easier to see the real-world impact of efficiency improvements on your fuel budget.
For an accurate measurement, use the full-tank method. Start by filling your fuel tank all the way to the top and reset your car's trip odometer. Drive as you normally would. The next time you visit the gas station, fill the tank completely again. Record the number of miles on your trip odometer and the exact amount of fuel it took to fill the tank. Using these two numbers in the formula will give you a very accurate GPM for that driving period.
Many factors can influence your car's fuel consumption. Your driving habits play a major role; for instance, aggressive driving with rapid acceleration and hard braking uses more fuel than smooth driving. The condition of your vehicle is also important. Things like underinflated tires, a clogged air filter, or an engine that needs a tune-up can all increase fuel use. Furthermore, your driving environment matters. Stop-and-go city traffic, driving in hilly areas, and using your air conditioner in hot weather will all lead to higher fuel consumption per mile.