Fair share each passenger should pay.

If a daily commute uses 8 of fuel and the car costs 20 a day in insurance, maintenance and depreciation, three passengers paying only 2.66 each in fuel leaves the driver 20 out of pocket on the running costs. A fair split is 7 each, covering both fuel and a proportional share of running cost.

What the result means

Each passenger pays the figure shown above. The driver covers their own share of running cost plus has the use of the car. If the carpool is one-way only, halve the daily figures or use the relevant trip-only number.

Many carpools use simpler fuel-only splits to keep things friendly. This calculator just shows what the fair number would be — the social negotiation is up to you.

Run it with sensible defaults

Using daily fuel cost of 8, daily running cost of 20, passengers of 3, the calculation works out to 7.00. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Daily Fuel Cost, Daily Running Cost, and Passengers — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

Total daily cost is fuel plus running cost. Fair per-person share divides this by passengers plus the driver. The driver effectively pays their own share, so cumulative passenger contributions cover the non-driver share of cost. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

When to actually change the habit

Most lifestyle spending delivers real value. The exceptions are the ones that stopped delivering months ago but got auto-renewed anyway, and the ones chosen out of defaults rather than preference. Run this, then audit for those two categories — that's where the easy wins live.

What this doesn't capture

The tool prices the money; it can't weigh the enjoyment. A coffee habit, gym membership, or streaming bundle might cost what the math says but deliver value that's harder to quantify. Use the number to make the trade-off visible — the decision is yours.