How the fuel cost calculator works
Enter your trip distance, your vehicle fuel efficiency in miles per gallon, and the price of fuel, and the tool estimates what the drive will cost in gas. It divides the distance by your MPG to find the gallons needed, then multiplies by the price per gallon. It also splits the cost between passengers and shows the round trip total.
Estimating fuel for a trip
The core math is simple: gallons equal distance divided by MPG, and cost equals gallons times price. So a 300 mile drive in a car getting 28 MPG uses about 10.7 gallons, which at 3.50 a gallon is roughly 37.50 one way. Real consumption varies with speed, terrain, load, and weather, so treat the figure as a close estimate.
City versus highway MPG
Use a realistic MPG for the kind of driving you will do. Highway figures are usually higher than city figures, and aggressive driving, heavy loads, roof boxes, and cold weather all lower efficiency. If you are unsure, check your trip computer average or your vehicle EPA combined rating and adjust down a little for headwinds and hills.
Sharing the cost
Splitting fuel between passengers is common for road trips and carpools. Enter how many people are sharing and the tool divides the round trip cost evenly. The cost per mile and cost per 100 miles figures make it easy to compare vehicles or to budget a longer journey.
Frequently asked questions
How do I calculate gas for a trip? Divide the distance by your MPG to get gallons, then multiply by the price per gallon.
How much does a 300 mile trip cost? At 28 MPG and 3.50 a gallon, about 37.50 one way before any variation in driving conditions.
What MPG should I use? Your real-world average; highway is higher than city, and cold or aggressive driving lowers it.
Related calculators: MPG, Car Lease, Brake Distance.