What xplit does

A trip holds activities: dinner on Friday, the boat, the museum, the taxi back. Each activity has its own list of people and its own transactions, so someone who skipped the museum pays nothing towards it. An activity can also stand on its own, for a single dinner that is not part of any trip.

A transaction is an amount, what it was for, who paid and, if you like, the date it was paid. Several people can pay towards the same activity, and the app adds it all up. Add a person to an activity and they join the trip as well, so you never type a name twice.

By default the cost of an activity is divided equally among the people in it. Give one or two of them a fixed amount and the remainder is split equally among the rest. That covers most of real life: the friend who only had a starter, the couple that took the bigger room, the person who left before dessert.

A refund or a returned deposit is a negative amount, entered the way you would write it. And someone who paid for an activity without taking part in it is still credited for what they paid, which sounds obvious until you meet a tool that gets it wrong.

Each person's balance is what they paid minus their share of everything they were part of. From the balances, xplit works out the transfers that settle everyone: it pairs the person who is owed the most with the person who owes the most, and keeps going until every balance is zero. Four people rarely need more than three payments.

You can look at it person by person, or by group. The result is the same money, grouped the way you will actually pay it. There is a longer explanation of the method on the blog.

Some people share a wallet: a couple, parents and their kids, two colleagues on one company card. Drag one onto the other and they become a group. The group's balance is the sum of its members' balances, so a couple that is owed 40 and owes 15 settles once, for 25, instead of twice.

Groups are named after their members until you rename them, belong to the trip, and are synced, so everyone the trip is shared with sees the same groups. Disband one and its members go back to settling on their own.

The owner of a trip makes an invitation link and decides what it grants: a look at the numbers, or full access to change them. Whoever opens the link signs in and joins with that access. Later you can change what each person may do, remove someone, replace the link, or stop sharing by link while everyone who already joined keeps what they have.

A shared trip is live. When someone else adds a cost, your screen updates while you are looking at it, and a small note tells you who else has the same page open.

Amounts are read the way people write them. $2,926.95, 2.926,95 € and 2 926,95 all mean the same thing, and Total: $24.50 incl. tax becomes 24.50. Only text with no number in it is refused.

Freeform edit opens any list as plain text, one entry per line, with the columns lined up. Paste rows straight from a spreadsheet, fix a typo in ten lines at once, or type the whole dinner in one go: date, amount, what it was for, who paid.

Not sure yet which activity a receipt belongs to, or who paid it? Add it with just the amount. It waits on the trip's Transactions tab, counted in the total but in nobody's balance, and the tab stays marked until you sort it. Nothing is final until everything is placed, and the app says so.

The browser keeps a full copy of your data, and every screen reads and writes that copy. So the app is instant, and it keeps working with no connection. Sign in with Google or Apple and the copy syncs with your account in the background: after each change, when the tab regains focus, and when the connection comes back.

Whatever you entered before signing in becomes part of the account. Open the same trip in two tabs, or on a phone and a laptop, and they agree. The iPhone app shares the same account, so a trip started on the phone is in the browser a moment later.

Export saves a trip or an activity as a single web page, laid out to be printed and with nothing loaded from elsewhere, or as plain text for pasting into a message. It lists what was paid, who took part, each share, the balances and who owes whom.

Undo and redo take back and redo whatever you changed, one step at a time, and the tooltip says which step. Charts at the top of a trip show who paid and what each person's share came to. And the app comes in light and dark, follows the device if you ask it to, and has a theme editor for people with opinions about orange.