Split Bill Calculator - Who Owes Whom

How Group Expense Settling Works

For every expense, the amount is divided equally among the people it was shared with, the payer is credited the full amount, and each participant is debited their share. Summing that over all expenses gives one net balance per person: positive means the group owes them, negative means they owe the group. A useful property of net balances is that they always sum to zero, so the tool can settle any history of expenses no matter how tangled.

The settle-up list uses a greedy algorithm: repeatedly match the largest debtor with the largest creditor and transfer the smaller of the two amounts. For a group of n people this needs at most n-1 transfers, far fewer than paying back each expense individually. A weekend trip with 3 people and a dozen shared costs typically collapses to just 2 transfers.

The per-expense checkboxes handle the situations that break naive bill splitting: the friend who skipped dinner but shared the taxi, or the couple who paid for their own museum tickets. Uncheck anyone who did not take part in a specific expense and their balance is untouched by it, while the cost is spread over the remaining participants only.

Everything stays in your browser, so you can total up a trip on your phone at the airport without creating an account or sharing the group's spending with a third-party app. For a single restaurant bill where you just need to add a service tip and divide by headcount, the Tip Calculator is quicker, and the Percentage Calculator covers ad-hoc share math like "what is 35% of 240".