Who owes whom? Settle shared costs

Calculator

Enter a name for each person and the amount they paid. Anyone who paid nothing gets a 0. The total is split equally between everyone in the list. It works for 2 to 16 people and calculates in euros. The pre-filled values are an example. What you enter stays in your browser and is neither stored nor sent anywhere.

How it is calculated

1. All amounts are converted to whole cents, so there are no rounding errors.
2. The total is divided by the number of people. If cents are left over, the first people in the list pay one cent more each.
3. A person’s balance is the amount they paid minus their share. Plus means they get money back, minus means they pay.
4. The calculator looks for the smallest number of transfers that brings every balance to zero. Up to 16 people it tries every possibility to do so.
5. If several solutions are equally good, the order of the list decides. The same input always gives the same transfers, and they settle every balance to the cent.

Example with four people

Lea pays €220.00, Tim pays €120.00, Jonas pays €20.00, Mia pays €40.00. That is €400.00 in total, so each share is €100.00. The balances: Lea +€120.00, Tim +€20.00, Jonas -€80.00, Mia -€60.00. 3 transfers are enough: Jonas pays Lea €80.00, Mia pays Lea €40.00 and Mia pays Tim €20.00. After that, everyone is at zero. How to deal with balances like these day to day is covered in debts between flatmates.

What the calculator does not do

It always splits equally between everyone in the list. It does not know unequal shares, expenses for only part of the group, currencies other than euros or repayments that have already been made. If you want to split rent by room size, the rent split calculator helps, and more models are covered in how to split flat costs fairly. For expenses that pile up over weeks, a calculator is tedious, because you have to enter everything again each time.

How ManaWG keeps this up to date

In ManaWG you enter every expense when it happens: who paid, who took part, split equally or with an individual amount per person. The app keeps each person’s balance and suggests transfers from it, using the same method as this calculator. Up to 16 open balances it picks the smallest number of transfers out of all possibilities; beyond that it uses a simpler method that can need more transfers. ManaWG does not move any money itself: you pay by bank transfer, in cash or however you like and mark the settlement as paid. At the start of each month an email statement with the suggestions arrives, and anyone can switch it off. The demo without sign-up shows what it looks like. More on the feature is on the shared expenses page.

Open source

ManaWG is open source under Apache-2.0, and the source code is on GitHub.