How should you split costs on a group trip?
Short answer
Split the shared costs evenly — accommodation, groceries, the rental car, group dinners — and let everyone pay for their own extras. Log each shared expense as it happens with who paid, and settle once at the end rather than continuously.
Decide what counts as shared
The arguments almost never come from the big obvious costs. They come from ambiguity: was that taxi shared? Was the bottle of wine three people drank a group expense? Define the categories on day one and the rest sorts itself out.
- Shared: accommodation, rental car and fuel, groceries, group meals agreed in advance
- Personal: flights, individual activities, souvenirs, anything anyone opts out of
- Grey area to settle in advance: taxis, drinks rounds, and the airport transfer
Log as you go, settle once
Someone pays, someone writes it down. That's the whole system. Trying to settle up in real time creates a stream of small transfers nobody tracks; leaving it entirely to the end means reconstructing a week from memory and bank statements.