A few things worth agreeing beforehand
Splitting fuel cost evenly between everyone in the car is the simplest and generally fairest approach for a one-off trip — it's what this calculator does. It's worth agreeing the split method before you set off rather than after, especially if someone is joining or leaving partway, or if the driver feels the cost of wear and tear should be factored in on top of fuel.
For a regular carpool (a shared commute, say), some groups prefer a rota where each person drives and pays for fuel on alternate weeks rather than splitting cash every trip — it avoids the need to settle up constantly, though it only works if everyone drives roughly equal amounts overall.
Frequently asked questions
Should the driver also pay a share?
That's a personal choice — some groups have the driver contribute like everyone else, others let the driver ride free in exchange for the hassle of driving and use of their car. This calculator simply divides the total cost by the number you enter, so include or exclude the driver from that number as you see fit.
What if people are joining or leaving partway through the trip?
For trips with changing passenger numbers, it's often simpler to work out a rough average number of people for the whole journey, or split the journey into segments and calculate each separately.
Does this cover tolls or parking?
No, this is a fuel-only split — add any tolls, congestion charges or parking evenly on top if relevant.