Gas split calculator
Work out the fuel cost for a road trip, then split it between riders. Use it as a gas calculator for trip planning, or as a gas money calculator once you know who's riding. Free, instant, and nothing to sign up for.
Trip details
Fuel cost
$37.50
10.7 gallons for 300 miles
- Cost per mile $0.13
- Split between 4 people
- Each person pays $9.37
That leaves $0.02 unsplit to the cent: round 2 payments up by a cent so the total matches exactly.
How to calculate gas cost for a road trip
To calculate gas cost for a trip, divide the distance by your vehicle’s fuel efficiency to get the gallons (or kWh) used, then multiply by the price per gallon or per kWh. A 300-mile trip at 28 MPG and $3.50 a gallon uses 10.7 gallons of fuel, costing about $37.50.
fuel cost = (distance ÷ MPG) × price per gallon
Gas vs. electric
The maths is the same either way, just with different units. Gas vehicles use miles per gallon and a price per gallon; electric vehicles use miles per kWh and a price per kWh. Both reduce to the same underlying question: how much does it cost to cover this distance in this vehicle?
Should the driver pay too?
As a carpool cost calculator, this comes down to which convention your group uses. Some split gas evenly between everyone in the car, driver included, since everyone benefits from the trip equally. Others let the driver ride free, since they are providing the vehicle, doing the driving, and taking on the wear and tear. Neither is more correct than the other: agree on the convention before the trip starts, not after the tank is empty.
Splitting gas with multiple cars
If your group is taking more than one car, work out each car’s fuel cost separately using that car’s own distance and MPG, then split each car’s cost only between the people who rode in it. Only pool the totals across cars if everyone is contributing to the group’s fuel evenly regardless of which car they rode in, which is less common but not unusual for a group that swaps cars partway through.
For everything else the group is sharing on the trip, food, accommodation, activities, the trip expense calculator tracks it all and works out who owes who at the end.
Common questions
How do you calculate gas cost for a trip?
Divide the trip distance by your vehicle’s fuel efficiency to get gallons (or kWh) used, then multiply by the price per gallon or per kWh. A 300-mile trip at 28 MPG and $3.50 a gallon uses 10.7 gallons, costing about $37.50.
How do you split gas money on a road trip?
Work out the total fuel cost for the trip, then divide it evenly between however many people are splitting it. If the driver rides free, split it only between the passengers instead of everyone in the car.
Should the driver pay for gas too?
There is no single right answer: some groups split gas evenly including the driver, others let the driver ride free since they are providing the car and doing the driving. Agree on which convention you are using before the trip, not after.
How do you calculate gas cost per mile?
Divide the price per gallon by your vehicle’s MPG. At $3.50 a gallon and 28 MPG, that is 12.5 cents a mile. Multiply by the trip distance to get the total fuel cost.
How do you split gas costs if you are taking multiple cars?
Calculate each car’s fuel cost separately using that car’s own distance and MPG, then split each car’s cost only between the people who rode in it. Only combine the totals if every rider is chipping in for the whole group’s fuel, not just their own car.
What if someone joins the trip partway through?
Split the fuel cost by distance actually ridden rather than an even split. Someone who joins for the last 100 miles of a 300-mile trip pays roughly a third of what someone who rode the whole way pays.
How much should I budget for gas on a road trip?
Multiply the total trip distance by your cost per mile (price per gallon divided by MPG). A 1,000-mile road trip at 12.5 cents a mile comes to about $125 in fuel, before tolls or parking.
Does this work for electric vehicles?
Yes. Switch to electric mode and enter your vehicle’s efficiency in miles per kWh and your electricity price per kWh instead of MPG and price per gallon. The maths is identical either way.