Method
How to calculate who owes who in a group
Almost every money argument between friends comes from confusing 'what I paid' with 'what I owed'. They are two different figures, and it is the gap between them — the balance — that decides who transfers money to whom.
Step 1: what each person paid
Go through every expense and credit it in full to whoever actually handed over the money. Who ordered it, booked it or suggested it makes no difference; only the payment counts. An expense paid by two people is entered as two separate lines.
Step 2: what each person owed
For each expense, divide the amount between the people it concerns, using the agreed key — equal shares, percentages, nights stayed. The shares of one expense must add up to exactly its amount: that check prevents every downstream error.
Then, for each person, add up all the shares that apply to them. That total is what they owed across the whole trip.
Step 3: the balance, and how to verify it
The balance is simply paid minus owed. Positive means the person fronted more than their share and the group owes them the difference. Negative means they need to top up.
| Person | Paid | Owed | Balance |
|---|---|---|---|
| Alex | £400.00 | £160.00 | +£240.00 |
| Bilal | £160.00 | £160.00 | £0.00 |
| Chloe | £80.00 | £160.00 | −£80.00 |
| Diane | £0.00 | £160.00 | −£160.00 |
Check: 400 + 160 + 80 + 0 = £640 paid, and 4 × 160 = £640 owed. The balances add to +240 − 80 − 160 = 0. If that total is not zero, an expense is missing.
Step 4: simplify the transfers
In the example above there are not four criss-crossing debts but two transfers: Diane sends £160.00 to Alex and Chloe sends £80.00 to Alex. Bilal does nothing. Every balance returns to zero.
The general rule: match the largest debtor with the largest creditor, clear what can be cleared, then repeat. A group of n people settles in fewer than n transfers.
Frequently asked questions
Why must all the balances add up to zero?
Because every pound spent is both paid by someone and owed by someone. Credits and debts describe the same money seen from two sides. If your total is not zero, an expense or a participant is missing.
Do I have to repay the exact person I owe?
No, and that is precisely what lets you cut the number of transfers. A balance is owed to the group, not to one named person: any combination of transfers that brings every balance back to zero is correct.
What about balances of a few pence?
Usually you fold them into the main transfer rather than leaving them hanging. A stray 1p balance can absolutely be written off by mutual agreement — as long as someone says so out loud.
Editorial review — Written and reviewed by the Pivunio team. The methods described here are the ones the app itself uses, and they are covered by automated tests.