Write it down when you pay
Most trip arguments start on the last day, when someone tries to rebuild the week from bank statements and a WhatsApp scroll. The fix is dull: log each payment within a minute of making it, with who paid and who it was for.
In Kitna Hua that is an amount, a payer and a list of names. Anyone in the trip can add it from their own phone, and it saves even with no signal.
Split among the people who used it
An equal split across the group is fine for the room and the cab. It stops being fair for the rafting two people sat out or the drinks one person never ordered. Split each expense among the people it was for and the totals come out right without anyone keeping a mental tally.
For uneven splits, use shares. A room shared by a couple and a friend is 2 shares and 1 share, and the app works out the rupees.
Settle the net, not every line
Paying back each expense on its own means dozens of tiny transfers. What matters is the gap between what each person paid and what their share came to. Some people are owed money and the rest owe it, and a group of five never needs more than four transfers to clear.
Kitna Hua works those transfers out and opens your UPI app with the amount filled in. Only the person who was owed can mark a payment as received, so nobody can settle a debt on someone else's behalf.