Gas Mileage Calculator

Calculate your vehicle's MPG, fuel cost per trip, cost per mile, and annual fuel spending. Compare against EPA averages and see how driving habits affect your wallet.

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Calculate MPG

US average: 14,263 miles/year (FHWA)

Trip Fuel Cost

Your Fuel Economy

Miles Per Gallon (MPG)
Cost Per Mile
Annual Fuel Cost
Gallons Per Year
Monthly Fuel Cost
L/100km
Annual CO₂ (lbs)

How You Compare (EPA Averages)

Vehicle TypeAvg MPGAnnual Costvs You
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Understanding Gas Mileage and Fuel Economy

Gas mileage — measured in miles per gallon (MPG) — tells you how far your vehicle travels on one gallon of fuel. Higher MPG means lower fuel costs. The EPA estimates fuel economy for every vehicle sold in the US, testing under controlled laboratory conditions. However, real-world MPG is typically 10-20% lower than EPA ratings due to driving habits, weather, terrain, and vehicle condition.

The formula is simple: MPG = Miles Driven ÷ Gallons Used. To track your MPG, fill your tank completely, reset your trip odometer, drive normally until the next fill-up, and divide the miles driven by gallons added. Do this over 3-4 fill-ups for an accurate average.

What Affects Your MPG

Research from Oak Ridge National Laboratory shows the following factors have the largest impact on real-world fuel economy: aggressive driving (rapid acceleration and braking) reduces MPG by 15-30%, highway speeds above 50 mph decrease efficiency by 7-14% for every 10 mph increase, proper tire inflation improves MPG by up to 3%, and excess weight (100 lbs) reduces MPG by roughly 1%. Air conditioning can reduce MPG by up to 25% in city driving but has minimal impact on highway fuel economy.

Average Fuel Economy by Vehicle Type (EPA 2024)

Vehicle TypeAvg MPG (Combined)Annual Fuel Cost*Annual CO₂ (lbs)
Hybrid50 MPG$9503,940
Compact Car35 MPG$1,3605,620
Midsize Sedan32 MPG$1,4906,160
All Passenger Vehicles27.5 MPG$1,7307,150
Small SUV / Crossover28 MPG$1,7007,030
Midsize SUV24 MPG$1,9808,200
Full-Size SUV19 MPG$2,50010,360
Pickup Truck20 MPG$2,3809,840
Minivan22 MPG$2,1608,940
Large Pickup / HD15 MPG$3,17013,120

*Based on 14,263 miles/year (FHWA average) at $3.45/gallon. CO₂ calculated at 19.6 lbs/gallon (EPA). Sources: EPA fueleconomy.gov, Federal Highway Administration.

Gas vs Electric: Annual Fuel/Energy Cost Comparison

VehicleEfficiencyAnnual Energy Cost*5-Year Fuel Savings vs 25 MPG
Gas (15 MPG truck)15 MPG$3,280+$7,250 more
Gas (25 MPG avg)25 MPG$1,970
Gas (35 MPG efficient)35 MPG$1,410$2,800 saved
Hybrid (50 MPG)50 MPG$985$4,925 saved
PHEV (75 MPGe)75 MPGe$750$6,100 saved
BEV (100 MPGe)3.3 mi/kWh$580$6,950 saved

*Gas at $3.45/gal, electricity at $0.134/kWh (EIA national avg). 14,263 miles/year. EV efficiency assumes 30 kWh/100 miles. Actual costs vary by location and driving patterns.

The True Cost of Driving: Beyond Fuel

AAA's 2024 "Your Driving Costs" study calculated that the average cost of owning and operating a new vehicle is $12,182 per year — or $0.724 per mile. Fuel is only about 15% of this total. The full breakdown: fuel ($1,730/year), insurance ($2,014), maintenance ($1,186), tires ($224), license/registration ($783), depreciation ($4,736), and financing ($1,509). For a complete picture of your commute costs including time and opportunity cost, use our Commute Cost Calculator.

The Department of Energy reports that fuel economy has improved 33% since 2004, from 20.8 MPG to 27.5 MPG for all new passenger vehicles. Despite this, total fuel spending has remained relatively flat because Americans drive more miles per year and gas prices have fluctuated. Track your spending patterns over time with our Subscription Cost Projector, and use the Discount Calculator to evaluate fuel reward programs that offer cents-off per gallon.

Frequently Asked Questions

How do I calculate my car's MPG?
Fill your tank completely, reset your trip odometer, and drive normally. At your next fill-up, note the miles driven and gallons added. Divide miles by gallons: 350 miles ÷ 12.5 gallons = 28 MPG. Repeat over 3-4 fill-ups for an accurate average.
Why is my real MPG lower than the EPA rating?
EPA tests are conducted under controlled lab conditions at moderate speeds without A/C. Real-world factors — aggressive driving, cold weather, short trips, highway speeds above 60 mph, heavy cargo, and low tire pressure — all reduce actual MPG. Real-world fuel economy is typically 10-20% below the EPA window sticker number.
How much does driving speed affect fuel economy?
Fuel efficiency peaks around 35-45 mph for most vehicles. Above 50 mph, every 10 mph increase costs roughly 7-14% in fuel efficiency due to aerodynamic drag. Driving 75 mph instead of 65 mph on a 300-mile trip costs about $5-8 extra in fuel but saves only 30 minutes.
Is it cheaper to drive a gas car or an electric car?
Per mile, electric vehicles cost roughly $0.04 vs $0.12-0.15 for gas vehicles (at national average electricity and gas prices). Over 14,000 miles/year, that's about $580 for an EV vs $1,700-2,000 for a gas car — saving $1,100-1,400 annually in fuel alone. However, EVs have higher upfront costs.
How much CO₂ does my car produce?
Burning one gallon of gasoline produces approximately 19.6 pounds of CO₂ (EPA). A car getting 25 MPG and driving 14,000 miles/year uses 560 gallons and produces about 10,976 lbs (5 metric tons) of CO₂ annually. The average American's total carbon footprint is about 16 metric tons.

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