Enter your odometer readings (start and end), fuel added, and gas price to calculate your MPG (miles per gallon). You'll get your fuel efficiency, total fuel cost, and cost per mile — all in one place. Switch between US (MPG) and metric (L/100km or km/L) units to match your preference.
Fuel Efficiency
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Distance Traveled
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Total Fuel Cost
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Cost per Mile
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Est. Annual Fuel Cost
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Gas mileage, measured in miles per gallon (MPG), describes how far your vehicle can travel on one gallon of fuel. A higher MPG means your car is more fuel-efficient. It depends on factors like your vehicle type, engine size, driving habits, tire pressure, and road conditions.
To calculate MPG, record your odometer reading when you fill up your tank, then fill up again and note the new odometer reading and the gallons added. Divide the miles driven (the difference between readings) by the gallons added. For example: 350 miles ÷ 11.5 gallons = 30.4 MPG.
Most passenger cars hold between 12 and 16 gallons, while trucks and SUVs typically hold 20 to 30 gallons. You can find your vehicle's exact tank capacity in the owner's manual or by searching your car's make and model online.
Modern vehicles use sensors to track fuel consumption and distance simultaneously. The onboard computer divides distance traveled by fuel consumed in real time. This gives you an instantaneous or trip-average MPG reading on your dashboard display.
It depends on your car's MPG. Divide 300 miles by your MPG to get the gallons needed. For a car getting 30 MPG, you'd need 10 gallons. At $3.50/gallon, that trip would cost about $35. Use this calculator to estimate the exact cost for your vehicle.
Key factors include driving speed (highway vs. city), tire pressure, vehicle weight, air conditioning use, engine condition, and fuel type. Aggressive acceleration and braking significantly reduce MPG. Keeping up with maintenance like air filter changes and proper tire inflation can noticeably improve efficiency.
You can improve MPG by maintaining steady speeds, avoiding rapid acceleration and hard braking, keeping tires properly inflated, removing unnecessary weight from your vehicle, and using cruise control on highways. Regular tune-ups, using the recommended motor oil, and combining errands into single trips also help.
MPG (miles per gallon) is the US standard — higher is better. km/L (kilometers per liter) is a metric equivalent where higher is also better. L/100km (liters per 100 kilometers) is common in Europe and Canada — lower is better since it measures how much fuel is consumed rather than how far you go per unit of fuel.