Guide
Splitting costs on a group trip when nobody does everything
Dividing the total by the number of people is only fair if everybody did everything — and on a real trip, nobody does. Here's how to keep the money honest without turning it into a second job.
Why the even split fails
Take eight friends and a week away. Five do the boat trip, three don't. Two skip the tasting menu. One arrives on day three. Divide the total eight ways and you have quietly charged three people for a boat they watched from the beach.
Groups usually notice this and start making exceptions by hand, which is where the spreadsheet becomes unmaintainable — every exception changes every row.
Split per item, by who was in
The reliable rule is that a cost is shared by the people who took part in that specific thing, and by nobody else. It sounds like more work, and by hand it is. It stops being work when the record of who was in for an activity is the same record that drives the split — decide once, and the arithmetic follows.
That includes the small stuff. Taxis, rounds, a supermarket run for six of you: these are ad hoc spends with their own list of who they covered, and they belong in the same running total as the big bookings.
Handling more than one currency
Foreign currency is where most group ledgers quietly go wrong. Somebody pays for dinner in euros, somebody else pays the ferry in sterling, and a third person converts both at whatever rate their banking app showed a fortnight later.
The fix is to record every cost in the currency it was actually paid in and convert it once, at the rate on the day, into a single trip currency. In The Triptych that conversion happens as you enter the amount, using daily reference rates, so the ledger is always in one currency and nobody does maths at the airport.
Settling up
- Work out each person's net position — what they consumed minus what they paid out — rather than settling item by item.
- Reduce it to the fewest possible payments. Eight people rarely need more than a handful of transfers between them.
- Give people a way to flag a cost they think is wrong before the settle-up, not after. A disputed item that's visible is a conversation; a surprise is an argument.
- Export the whole thing. Everyone should be able to see the workings, not just the final number they owe.
All four of those are built in: the debt engine nets each person off, proposes the shortest set of payments, supports disputing an individual item, and exports the full trip detail with debts as a PDF or CSV.
Related reading
Try it on a trip that isn't real yet
Every new account gets a sandbox trip with a fictional group, so you can walk the whole loop — propose, vote, record costs, settle up — before spending anything.