Carpool Savings Calculator
Enter the one-way distance, days per week, your driving cost per km, and how many people share the ride. The calculator splits the annual cost per person, shows what each sharer saves against driving alone, and the CO₂ the arrangement removes.
Ride-hailing apps price a trip; pool calculators usually stop at fuel. This one splits the honest all-in driving cost, puts a kilogramme figure on the emissions, and - the part apps skip - sets the ground rules that decide whether a pool survives its first late meeting.
How to use
- Enter the one-way distance and days per week you actually commute - 46 working weeks keeps holidays honest.
- Use an all-in per-km cost (0.45 default), not fuel alone, so the driver is not quietly subsidising passengers.
- Pick the group size and read each person's saving; agree the late-evening rule before the first shared ride, not after.
Frequently asked questions
How is carpool cost normally split?
By distance-driven cost share: total running cost divided by occupants, sometimes with the driver keeping a larger share for the ownership risk. Fuel-only splits undercharge the driver by about two-thirds of the true cost per km.
Does carpooling affect my insurance?
Genuine cost-sharing between commuters is treated as shared expenses, not commercial hire, by mainstream insurers. Charging strangers a profit per seat is different and needs hire-and-reward cover - a pool of colleagues is fine.
How much CO₂ does carpooling save?
A typical petrol car emits about 170 g of CO₂ per km, so a 25 km each-way commute driven 5 days a week books roughly 2 tonnes a year. Three sharers in one car remove one whole car - about 1.3 tonnes saved per person, per year.
What kills a carpool in practice?
Schedule rigidity: one person's late meeting strands the others, twice, and the pool dies. Pools that last agree a written norm - a departure window, a solo-day allowance each month, and a backup driver - before the first missed connection, not after.