Fuel Cost Calculator
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Calculate exactly how much fuel will cost for any road trip. Enter distance, MPG, and gas price.
Trip Fuel Cost
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📐 Formula
Gallons = Distance ÷ MPG. Cost = Gallons × Price per Gallon. Cost per Mile = Cost ÷ Distance
How to Use the Fuel Cost Calculator
Enter your trip distance
Input the total one-way distance in miles or kilometres. Use your GPS app's routing distance rather than straight-line distance for accuracy.
Enter your vehicle's fuel efficiency
Input MPG (miles per gallon) for US measurement or L/100km for metric. Find your vehicle's EPA-rated MPG at fueleconomy.gov or check your dashboard fuel economy display.
Enter the current fuel price
Input the current price per gallon or per litre at your local station. Use a real-time resource like GasBuddy for the most accurate price.
Toggle for round trip
Select the round-trip option to double the fuel calculation automatically. For multi-stop trips, calculate each segment separately and sum.
How to Calculate Fuel Cost Manually
The formula is: Fuel Cost = (Distance ÷ MPG) × Price per Gallon. For a 350-mile trip in a car getting 32 MPG with gas at $3.50/gallon: (350 ÷ 32) × $3.50 = 10.9 gallons × $3.50 = $38.28. In metric: Fuel Cost = (Distance km × L/100km ÷ 100) × Price per Litre. For a 600km trip at 8L/100km with fuel at $1.85/L: (600 × 8 ÷ 100) × $1.85 = 48 litres × $1.85 = $88.80.
Factors That Change Your Real-World Fuel Economy
EPA ratings are measured under controlled conditions and frequently differ from real-world driving. Key factors that reduce fuel economy: highway speeds above 60mph (aerodynamic drag increases exponentially — fuel economy at 75mph is typically 15–20% worse than at 55mph); air conditioning (adds 5–25% fuel consumption depending on conditions); aggressive acceleration and braking (smooth driving saves 10–40%); cold weather (gasoline engines warm up inefficiently — short cold trips in winter can cut MPG in half); tire pressure (under-inflated tires by 10 PSI reduces MPG by approximately 3%). For a realistic trip estimate, reduce your car's rated MPG by 10–20% for highway driving with AC and moderate speeds.
Comparing Trip Costs: Car vs Alternatives
When evaluating driving versus flying or taking the train, fuel cost is only part of the picture. Add parking ($20–$60/day in cities), tolls (I-95 corridor from Boston to DC totals over $40 in tolls), vehicle wear (AAA estimates $0.09–0.12 per mile for tires, oil, and depreciation on a typical car), and driver fatigue for long trips. For trips under 200–300 miles, driving is almost always cheapest and often fastest door-to-door. For 400–700 miles, budget airlines often compete. Above 700 miles, flying total cost is frequently lower than driving when vehicle wear is included.
Fuel Cost by Vehicle Type: What to Expect
Fuel costs vary dramatically across vehicle categories. A compact sedan averaging 35 MPG costs approximately $0.10/mile at $3.50/gallon. A midsize SUV at 25 MPG costs $0.14/mile — 40% more per mile. A full-size pickup truck at 18 MPG reaches $0.19/mile. A hybrid averaging 50 MPG drops to $0.07/mile. Over a 500-mile road trip, the difference between the hybrid and the pickup is over $60 — nearly the cost of a night's accommodation.
How to Calculate Fuel Cost by Hand: Worked Example
Take a 350-mile trip in a vehicle averaging 28 MPG, with fuel priced at $3.45 per gallon.
Step 1 — calculate gallons needed. 350 ÷ 28 = 12.5 gallons.
Step 2 — multiply by price per gallon. 12.5 × $3.45 = $43.13 total fuel cost for the trip.
How does this compare to an electric vehicle over the same distance?
An EV averaging roughly 0.30 kWh per mile at an electricity price of $0.15/kWh: 350 × 0.30 × $0.15 = $15.75 — less than half the gas vehicle's cost for the identical trip. The comparison narrows considerably on longer road trips requiring public fast-charging (often priced well above home electricity rates) and widens further for home-charged local driving, which is why EV cost comparisons depend heavily on where and how the vehicle is charged, not just the vehicle's efficiency rating alone.
Why Does Real-World Fuel Economy Rarely Match the Sticker MPG Rating?
What conditions most reduce real-world MPG below the EPA rating?
Highway EPA figures assume steady-speed cruising; city driving with frequent stops, aggressive acceleration, cold weather (which increases engine warm-up time and rolling resistance), heavy cargo or roof racks, and running the air conditioning can each reduce real-world fuel economy by 10–25% below the rated figure. A vehicle rated at 28 MPG might realistically average 22–24 MPG in cold-weather city driving with AC running — a gap large enough to meaningfully change the fuel cost calculation above.
How much does speed alone affect fuel cost on a highway trip?
Fuel efficiency for most vehicles peaks somewhere in the 50–60 mph range and declines measurably above that — driving at 75 mph instead of 65 mph commonly reduces fuel economy by roughly 10–15% due to increased aerodynamic drag, which scales with the square of speed. On the 350-mile trip above, that difference alone could add $4–$6 to the fuel bill, independent of traffic or route.
Does the type of vehicle change more than just the MPG number?
Beyond fuel economy, larger vehicles often require premium fuel (adding 10–15% to the per-gallon price) or have larger tanks that make a "fill-up" feel larger in absolute dollars even at the same per-mile cost — worth separating "cost per mile" from "cost per fill-up" when budgeting, since the two tell different stories about a trip's real fuel expense.
Frequently Asked Questions
The average new car gets about 28–32 MPG combined. SUVs typically get 22–26 MPG. Hybrids get 40–55 MPG. Electric vehicles are measured in MPGe (miles per gallon equivalent).
Maintain steady speed, use cruise control on highways, keep tires properly inflated, remove excess weight, and get regular maintenance. Aggressive acceleration and braking can reduce MPG by 15–30%.
Divide the trip distance by your MPG to get gallons needed, then multiply by the gas price. This calculator does it automatically.
Sources & Methodology
Calculations are based on the most current publicly available data from authoritative government and industry sources: