Gas Mileage Calculator

Calculate fuel economy in MPG, km/L, and L/100km using odometer readings or trip distance. Includes cost analysis, vehicle comparison, and fuel savings.

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Gas Mileage by Odometer Readings

Record your odometer before and after a trip, then enter how much fuel you added when you refilled. Includes optional cost analysis.

Your current odometer reading after the trip
Your odometer reading when you last filled up
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Gas Mileage by Trip Distance

Enter the total distance traveled and the amount of fuel used during that trip.

For rental/expense reimbursement calculations
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Multi-Fill Trip Tracker

Track fuel economy across multiple fill-ups for a long trip or monthly tracking. Enter each fill-up's odometer reading and fuel amount.

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Compare Two Vehicles

Compare fuel economy and annual costs between two vehicles side by side.

🚗 Vehicle A
⚡ Vehicle B
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Fuel Savings Calculator

Calculate how much you would save by improving your car's fuel economy — through better driving habits, maintenance, or a new vehicle.

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9 Ways to Improve Gas Mileage

Practical tips from the US Department of Energy to maximize your fuel efficiency and save money at the pump.

1
Drive a Fuel-Efficient Vehicle
4-wheel drive uses more fuel than FWD/RWD. Check fueleconomy.gov for the latest fuel efficiency rankings before buying a car.
2
Maintain Correct Tire Pressure
Under-inflated tires reduce gas mileage by 0.3% per PSI drop. Check pressure monthly and inflate to the manufacturer's recommendation.
3
Drive at 55 mph for Optimal Efficiency
Vehicles are 3% less efficient at 60 mph, 8% at 65 mph, 17% at 70 mph, 23% at 75 mph, and 28% at 80 mph compared to 55 mph.
4
Avoid Aggressive Driving
Smooth acceleration and gentle braking can improve fuel efficiency by 15–30% on highways and 10–40% in stop-and-go traffic.
5
Keep Your Vehicle Well-Maintained
Using the correct motor oil improves mpg by 1–2%. A faulty oxygen sensor can reduce mileage by up to 40%. Change air filters regularly.
6
Remove Unnecessary Weight
Every 100 lbs of extra weight reduces MPG by about 1%. Remove unused cargo, roof racks, and bike racks when not needed.
7
Roll Up Windows on the Highway
Open windows create drag at high speeds. On the highway, AC is actually more efficient than open windows due to reduced aerodynamic drag.
8
Use Air Conditioning Wisely
AC can reduce fuel economy by up to 25% in hot weather. Don't run AC at full blast when idling. It is more efficient when the car is moving.
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Avoid Unnecessary Idling
An idling vehicle gets 0 mpg. Turn off your engine if you're stopped for more than 60 seconds. Idling burns 0.2–0.5 gallons of fuel per hour.
MPG Reference Chart
Excellent: 40+ mpg (hybrids, small cars)
Good: 30–40 mpg (sedans, compact SUVs)
Average: 20–30 mpg (mid-size SUVs, trucks)
Below Average: Under 20 mpg (large trucks, older vehicles)