At the gas station, fill your tank to the auto-shutoff point. Don't top off—it can damage your evaporative emissions system and skew measurements.

Set your trip odometer to zero at the pump. If you don't have a trip odometer, note your current mileage.

Use your car as you normally would. Mix of city and highway driving gives the most representative results. Avoid tracking during unusual trips.

At your next fill-up, fill to the same auto-shutoff point. Note the gallons pumped and your trip odometer reading (or calculate miles driven).

Divide miles driven by gallons used. Example: 300 miles ÷ 12 gallons = 25 MPG. Track over several fill-ups for a reliable average.

Enter your distance and fuel used above for instant results, including cost per mile and efficiency rating compared to average vehicles.

Highway driving is typically 20-30% more fuel-efficient than city driving due to constant speed and less braking. Stop-and-go traffic is the worst for MPG.

Cold weather reduces fuel economy 10-20% due to longer warm-up times, increased air density, and winter fuel blends. Hot weather with A/C can reduce MPG 5-25%.

Aggressive driving (rapid acceleration, hard braking, speeding) can lower MPG by 15-30% on highways and 10-40% in city traffic. Smooth, steady driving maximizes efficiency.

Under-inflated tires increase rolling resistance. Every 1 PSI drop below optimal pressure reduces fuel economy by about 0.2%. Check monthly and before long trips.

Extra weight reduces MPG—about 1% per 100 lbs. Roof racks and cargo boxes increase aerodynamic drag, reducing highway MPG by 2-8% (even more at higher speeds).

A well-tuned engine with clean air filters, fresh oil, and properly functioning oxygen sensors optimizes fuel efficiency. Neglected maintenance can reduce MPG by 4% or more.

Fuel economy drops rapidly above 50 mph. Each 5 mph over 50 is like paying an extra $0.20-$0.30 per gallon. Use cruise control on highways for consistent speed.

Look ahead and coast to stops instead of braking hard. Accelerate gradually from stops. This 'hypermiling' technique can improve MPG by 10-20%.

Idling gets 0 MPG. Modern cars don't need to 'warm up'—just start and go gently. Turn off the engine if stopped for more than 60 seconds.

Remove roof racks when not in use. Keep windows closed at highway speeds (A/C is more efficient above 40 mph). Avoid driving with the tailgate down.

Remove unnecessary items from your trunk. Don't haul golf clubs or tools you don't need. Every 100 lbs reduces MPG by about 1%.

A warmed-up engine is more efficient. Combine errands into one trip. Avoid rush hour when possible—idling in traffic kills MPG.

Simulates urban driving with frequent stops, low speeds, and idling. Includes cold starts. Represents a worst-case scenario for most drivers.

Simulates highway driving at higher speeds with no stops. Usually the highest rating. Realistic if you do mostly freeway commuting.

Weighted average: 55% city, 45% highway. The 'headline' number on window stickers. Good overall estimate for mixed driving.

Most drivers achieve 10-15% lower than EPA estimates. Your driving style, terrain, and conditions affect actual results. Track your own MPG for accurate budgeting.