Fuel Cost Calculator
Use this fuel cost calculator to estimate how much you will spend on gas for a trip. Enter your distance, fuel efficiency, and gas price to calculate total travel cost. This tool is useful for road trips, commuting, and travel budgeting.
Trip Details
Cost Estimate
Enter trip details to calculate fuel cost.
How Fuel Cost Is Calculated
Fuel cost depends on three factors: distance, fuel efficiency, and fuel price. The formula is: Gallons Needed = Distance ÷ MPG, and Total Cost = Gallons × Price Per Gallon. For a 300-mile trip in a car that gets 28 MPG with gas at $3.60/gallon: 300 ÷ 28 = 10.7 gallons × $3.60 = $38.57.
Real-world fuel efficiency often differs from the EPA estimate on the window sticker. Highway driving typically matches or exceeds the EPA highway number. City driving, frequent acceleration, cargo weight, roof racks, aggressive driving, cold temperatures, and tire under-inflation all reduce your actual MPG. For a road trip, use highway MPG for the estimate and add 10–15% as a buffer for real-world variation.
Fuel Cost for Commuting and Annual Planning
Annual fuel cost is one of the largest variable expenses of car ownership — often underestimated. At 15,000 miles/year in a 28 MPG vehicle with gas at $3.50/gallon: 15,000 ÷ 28 = 536 gallons × $3.50 = $1,875/year. Compare vehicles by calculating annual fuel cost at your typical mileage — the difference between a 20 MPG SUV and a 35 MPG hybrid is 214 gallons/year, or about $750 at $3.50/gallon. Over 5 years, that gap is $3,750, which can significantly affect total cost of ownership.
Frequently Asked Questions
How do I find my car's actual MPG?
The most accurate method: fill your tank completely, reset your trip odometer to zero, drive normally until the tank is low, fill up completely again, and record the gallons added and miles driven. MPG = miles driven ÷ gallons added. Repeat over several fill-ups and average the results for the most reliable figure. Your car's onboard computer displays an estimated MPG in real time, but it tends to read optimistically — the fill-up method is more accurate. Apps like GasBuddy and Fuelly let you log fill-ups over time and track your long-run average.
How much does driving style affect fuel efficiency?
Significantly — aggressive acceleration and braking can reduce MPG by 15–30% compared to smooth, steady driving. The EPA estimates that every 5 mph over 50 mph is equivalent to paying $0.22 more per gallon (at $3.00 base price). Carrying an extra 100 pounds reduces fuel economy by about 1%. Using air conditioning at highway speeds reduces MPG by roughly 5–15%. On the other hand, using cruise control on the highway, maintaining proper tire inflation (recommended PSI, not max), and accelerating gently can recover most of that lost efficiency without changing your destination or schedule.
Is it worth driving farther to find cheaper gas?
Usually not. If you save $0.10/gallon on a 15-gallon fill-up, you save $1.50. Driving 2 extra miles each way to get there costs about 14 cents per mile to operate (AAA estimates), or $0.56 for the 4-mile round trip — so you net about $0.94. If the cheaper station is 5 miles out of your way, the math barely breaks even and you've spent 10+ minutes of your time. The exception: if you are going to pass a cheaper station anyway on a long trip, filling up there instead of at the next exit is pure savings. Use GasBuddy to find stations along your planned route, not detours from it.