Fuel Cost Calculator
Free fuel cost calculator. Estimate the gas cost for any trip from distance, MPG, and price per gallon — perfect for road trip planning and reimbursements.
Quick answer
Trip fuel cost = (distance ÷ MPG) × price per gallon. For a 1,000-mile road trip in a 30 MPG car at $3.50/gallon, that's about $117 in gas. Halve the cost by halving the distance, the price, or doubling the MPG.
Fuel Cost / Road Trip Calculator
How it works
Calculates the total fuel cost of a trip given the distance, your vehicle's MPG, and the price per gallon. Also computes gallons needed and cost per mile so you can compare vehicles or trip options.
When to use it
Use this before a road trip to budget gas costs, when comparing fuel-efficient cars, when deciding whether to drive vs fly for a long trip, or when calculating mileage reimbursement for work travel.
Common mistakes
Using EPA city MPG for a highway trip (or vice versa). Real-world MPG varies based on driving style, terrain, weather, and load. Use the combined MPG number for mixed driving and add a 10–15% buffer for headwinds or hills.
How the fuel cost calculator works
Three inputs determine fuel cost: how far you're driving (in miles), the vehicle's fuel economy (in miles per gallon), and the price of gas (in dollars per gallon). Distance ÷ MPG = gallons needed. Gallons × price = cost. The calculator also shows per-person cost if you split with passengers — the most efficient way to lower cost-per-traveler is to fill the empty seats, not switch to a more efficient car.
When to use it
Planning a road trip and deciding how much to budget for gas. Comparing the total cost of driving vs. flying for medium-distance trips (typically driving wins under 500 miles for 2+ people, flying wins over 1,000). Setting fair fuel reimbursement for shared rides. Computing the real cost of a daily commute — for a 30-mile round-trip in a 25 MPG car at $3.50/gallon, that's $4.20/day or roughly $1,050/year.
Common mistakes
- Using EPA-rated MPG instead of real-world. The window-sticker MPG rating is a controlled-conditions test. Real-world MPG is typically 10-20% lower, especially in stop-and-go traffic, cold weather, or with a roof rack.
- Forgetting the round trip. A 'trip distance' of 200 miles is one way. Round trip costs are 2x.
- Underestimating in-trip side trips. Tourists rarely drive the most direct route. Add 10-15% to your one-way mileage estimate to cover detours, sightseeing, and getting lost.
Frequently asked questions
How do you calculate the fuel cost of a trip?
Divide trip distance (miles) by your car's MPG to get gallons needed, then multiply by the price per gallon. Example: a 600-mile trip at 30 MPG and $3.50/gallon = (600 ÷ 30) × $3.50 = $70 in gas.
What's the average MPG of a U.S. car?
The U.S. light-duty fleet average is about 25 MPG combined city/highway as of 2023. New cars sold today average closer to 28-30 MPG. Hybrids exceed 45 MPG; large SUVs and trucks often see 18-22 MPG.
Is it cheaper to drive or fly?
For 2+ people on a trip under 500 miles, driving is almost always cheaper. Flying wins on time, especially over 800 miles or for solo travelers. Pure cost favors driving up to about 1,000 miles for a family of 4.