Gas Mileage Calculator

Miles per gallon, or MPG, tells you how far your vehicle travels on a single gallon of fuel, and it's the standard way to compare fuel efficiency between cars, trucks, and driving habits. To calculate it, you simply divide the number of miles you drove by the number of gallons of fuel it took to drive them. Fill your tank, reset your trip odometer, drive normally until you need to fill up again, and then divide the miles on the odometer by the gallons it took to refill the tank.

MPG can vary quite a bit for the same vehicle depending on conditions. Highway driving at a steady speed typically gets better mileage than stop-and-go city traffic, since braking and re-accelerating burns extra fuel. Carrying heavy loads, driving aggressively, underinflated tires, and cold weather can all lower your MPG, while smooth, moderate-speed driving tends to improve it. Tracking your MPG over several fill-ups gives a more reliable picture than relying on a single tank.

Once you know your MPG, you can translate it into a cost per mile, which is often more useful for budgeting than the MPG figure itself. Cost per mile is simply the price of a gallon of gas divided by your MPG: a car getting 30 MPG with gas at $3.60 a gallon costs about 12 cents per mile to fuel, while a less efficient vehicle at 15 MPG would cost twice that, around 24 cents per mile, for the exact same trip. Multiplying cost per mile by the distance of a trip, or by your total gallons for a fill-up, gives you the total fuel cost, which makes it easy to compare what different vehicles or driving habits actually cost you over a commute, a road trip, or a full year of driving.