Fuel Economy Calculator
Find your vehicle's fuel economy in miles per gallon by entering distance driven and fuel consumed. Use this after a fill-up to track efficiency and spot changes in performance.
About this calculator
Fuel economy measures how far a vehicle travels per unit of fuel consumed. The formula is straightforward: MPG = distance / fuel_used, where distance is in miles and fuel_used is in gallons. A higher MPG value means better efficiency and lower fuel costs per mile. Tracking your MPG over time can reveal engine issues, changes in driving habits, or the effect of tire pressure on efficiency. For example, aggressive acceleration, underinflated tires, and carrying excess weight all reduce MPG. Comparing your calculated MPG to the manufacturer's EPA rating tells you how your real-world driving compares to the tested standard.
How to use
Suppose you drove 350 miles and used 12.5 gallons of fuel. Plug the numbers into the formula: MPG = 350 / 12.5 = 28 MPG. That means your vehicle travels 28 miles for every gallon of gasoline burned. If your car's EPA rating is 32 MPG highway, this result suggests your driving conditions or habits are reducing efficiency. Try reducing highway speed or checking tire pressure to close the gap.
Frequently asked questions
How do I calculate my car's miles per gallon accurately?
To get an accurate MPG reading, fill your tank completely, reset your trip odometer to zero, and drive normally until your next fill-up. Record the miles driven and the exact number of gallons it takes to refill the tank. Divide miles driven by gallons used to get your real-world MPG. Repeat over several tanks for a reliable average, since a single tank can be skewed by driving conditions.
What is considered good fuel economy for a car?
Good fuel economy depends on the vehicle class. For compact and midsize sedans, 30–40 MPG is considered efficient. SUVs and trucks typically range from 18–28 MPG in combined driving. Hybrid vehicles often achieve 45–55 MPG, while plug-in hybrids and EVs can exceed 100 MPGe. The EPA publishes fuel economy ratings for every model year at fueleconomy.gov, which is a useful benchmark for comparison.
Why does my actual MPG differ from the EPA estimate?
EPA estimates are measured under controlled laboratory conditions that don't fully replicate real-world driving. Factors like stop-and-go traffic, high-speed highway driving, cold weather, air conditioning use, roof racks, and cargo weight all reduce fuel efficiency. Aggressive acceleration and braking are among the biggest culprits. Regular maintenance — clean air filters, fresh spark plugs, and properly inflated tires — helps keep your actual MPG as close to the EPA figure as possible.