Gas & Trip Cost Calculator
Estimate what a drive really costs in fuel — then split it fairly between everyone in the car.
How to use this calculator
Enter the one-way distance of your trip in miles, your car's fuel efficiency in miles per gallon (MPG), and the price you pay per gallon of gas. If you are driving there and back, tick Round trip to double the distance. To share the cost, set the number of people in the car and we will divide the total evenly. Everything updates instantly as you drag the sliders, so you can quickly compare a slower, fuel-efficient route against a faster one.
How this is calculated
The math is simple. First we work out the distance: if Round trip is ticked, we double the miles you entered. Then we divide that distance by your MPG to get the gallons of fuel used, and multiply by the price per gallon to get the total cost. The per person figure is the total divided by the number of travellers, and the per mile figure is the total divided by the distance driven — a handy way to compare the running cost of different cars or trips.
A worked example
Say you are driving 300 miles in a car that does 28 MPG, with gas at $3.50 a gallon. That trip burns about 10.7 gallons, costing roughly $37.50 in fuel. Tick Round trip and the distance becomes 600 miles, so you use about 21.4 gallons and pay around $75. Split that round trip between four people and each person owes just under $19 — far cheaper than four separate drives or train tickets. At those numbers the cost works out to about $0.13 per mile, a useful benchmark for budgeting future road trips.
Tips to lower your fuel cost
- Drive smoothly — gentle acceleration and steady speeds can improve real-world MPG noticeably versus hard stops and starts.
- Keep tyres inflated — under-inflated tyres add rolling resistance and quietly waste fuel on every mile.
- Lose the dead weight — roof boxes, heavy loads and extra drag all push your gallons-per-mile up.
- Shop for cheaper gas — prices vary a lot between stations; even 20 cents a gallon adds up on a long drive.
- Carpool — the single biggest lever on cost per person is simply putting more people in the car.
Should you go electric?
If fuel is a big part of your driving budget, it is worth comparing a gas car against an electric one, where the "fuel" is electricity priced per kilowatt-hour. Charging at home is often far cheaper per mile than filling up at the pump, though the gap depends on local gas and electricity prices. Run your own numbers with our EV vs gas calculator to see which car would actually save you money over the miles you drive each year.