Before you share the bill

Agree on a few simple rules before the trip starts.

PRACTICAL GUIDE · START SMALL PAPER CO.

Choose the currency in which you will record costs. If you convert a receipt, agree on the rate and record it; do not assume automatic conversion.
Agree on who joins each expense. A person who skips an activity should not silently be included in its cost.
For unequal shares, write down the agreed units and check that everyone understands them. Family-size and accommodation-night rules need explicit discussion.
Keep receipts and record repayments separately. Review the entries together before using a suggested settlement.