Who owes whom
How it settles
Everyone's share is the trip total divided by the number of travellers. Cents that will not divide are handed out one each rather than landing on whoever happens to be last, so the shares sum to what was actually spent without one person quietly carrying the rounding. Each person's balance is what they paid minus what they owed. Positive means the group owes them.
The payments underneath are worked out by repeatedly matching whoever is owed the most against whoever owes the most. That gives at most one payment fewer than there are people, rather than everyone paying everyone. Four people usually settle in two transfers instead of twelve.
If the trip was in another currency
Converting each expense yourself with today's rate is where group balances quietly stop matching anyone's statement. Your card was charged at the network rate on the day the charge settled, plus a foreign transaction fee. Those are the numbers the group actually owes against.
Footnote takes the charge from the bank with its original amount, its converted amount, and the rate already attached, so nobody types a rate in. There is more on picking a rule and holding it in splitting expenses in another currency.
Or start free and let the trip settle itself as the charges post.
Settle it with the group
You have the payments that settle it. Footnote keeps the split, tracks who has paid, and every share opens back to the charge behind it. No account, no download, and the people you send it to need neither.