Fuel Economy Calculator
Calculate your actual MPG, annual fuel cost, and see how much better economy saves you.
What Affects Real-World MPG vs. EPA
EPA ratings are measured in controlled lab conditions. Real-world MPG is typically 15–20% lower due to cold engine starts (especially in winter), air conditioning use, highway speeds above 65 mph (aerodynamic drag increases as the square of speed), cargo weight, and under-inflated tires. City driving involves constant acceleration and braking which wastes energy as heat.
Hypermiling Tips
To maximize fuel economy: maintain steady speeds using cruise control on highways, keep tires inflated to the door jamb specification, remove roof racks and cargo carriers when not in use, accelerate gently and coast to stops, and avoid idling for more than 30 seconds. Each 5 mph over 50 mph costs roughly 7–14% in fuel economy.
How to Calculate MPG at the Pump
Fill up completely, reset your trip odometer. Drive normally. Fill up again completely. Divide the miles driven by the gallons pumped at the second fill-up. This is more accurate than the car's instant MPG readout, which can read 5–10% optimistically on some vehicles.