Rosa here. Seven expenses, four of us, and it comes down to three payments. I've put in who paid and who was in on each line. Check yours. You can change any line and the answer redoes itself as you type, but only on your own screen, so tell me what I got wrong.
People
Expenses
How it's worked out
Each expense, with its tip, is split in whole cents between the people ticked. If it won't divide evenly, the odd cent goes to whoever paid, or to the first person ticked when the payer wasn't in on it.
Your balance is what you paid minus your shares. Plus means the group owes you.
The page then finds the smallest number of payments that brings every balance to zero.