Split shared expenses and see who pays who

Six people on a week away generate thirty or forty expenses and, if everybody pays everybody back the amounts those expenses literally imply, something like twenty separate transfers. Almost all of them cancel out.

What this page does instead is work out each person's net position — everything they paid, minus everything that was their share — and then match the people who are owed against the people who owe, largest first. That always settles the whole group in at most one payment fewer than there are people: five payments for six people, and usually fewer, because anybody who happens to be square already drops out entirely.

It is worth understanding because the short list looks wrong the first time you see it. Ana buys the groceries, Ben buys the petrol, and the page tells Cal to pay Ana for both — Cal never bought anything from Ben, so why is Ben not in the list? Because Ben's petrol money comes back to him out of what somebody else owes him, and routing Cal's payment through Ben as well would move the same money twice. The list is not a record of what happened; it is the shortest way to undo it.

Most expenses split equally between everyone, which is the default and needs no thought. The other two modes exist for the two situations where an equal split is the thing people actually argue about.

Choose **by shares** when the group is not made of equal units. Two people sharing a double room are one room, not two, so the accommodation goes two shares to their one. A family of four in a house with two couples is four shares to two and two. Shares are the right tool whenever the ratio is stable across several expenses — you set it once per expense and never do arithmetic.

Choose **exact amounts** when the bill itemises and people ordered differently. Restaurant bills are almost the only real case: three of you had the set menu and one had a starter and tap water, and splitting equally means that person is subsidising the wine. Type what each person actually owes. If the amounts do not add up to the total you typed above them, the page trusts the amounts and restates the total, because the parts are the thing people will check.

You can also take somebody out of a single expense entirely without making it complicated: tap their name off, and that expense divides between whoever is left. Everyone else's expenses are untouched.

Ten pounds split three ways is not three equal shares. It is 3.34, 3.33 and 3.33, and some program somewhere has to decide who pays the extra penny.

A surprising number of splitting tools get this slightly wrong, and the symptom is always the same: the shares add up to a penny less than the bill, so a total of £10.00 shows as £9.99 and nobody can see why. It happens because the obvious way to write the calculation — divide, round each share, add them up — has no step that checks the answer against what was actually spent.

This page distributes the remainder instead of rounding it away. Every share is the exact floor of the division, and then the leftover pennies go one each to the people with the largest fractional claim on them. The shares of every expense add up to that expense, always, and the balances across the whole group add up to exactly zero — which is why the settle-up can be trusted to clear completely rather than leave a few pence floating.

It is a small thing that matters out of proportion to its size. A ledger that is a penny out is a ledger somebody will re-add by hand, and then they may as well have used a spreadsheet.

The share link holds the whole ledger, so you can send it to whoever is checking your arithmetic and they will see every figure. Two things follow from that, and both are worth knowing before you send one.

Anyone with the link can read the ledger. There is no password on it, because there is no server to hold one — the names and amounts are in the link itself. That is the same property that keeps your ledger private from us, and it cuts both ways.

They cannot add to it. If they log an expense and send the link back, you have two ledgers and the newer one wins by accident. One person keeps the ledger, everyone else reads it.

There are two ceilings, and they are different. One ledger holds up to 100 expenses between up to 16 people, which is past any trip we can think of and is there so a hand-edited link cannot ask your browser to draw a hundred thousand table cells. Separately, a long ledger eventually outgrows what a URL can be pasted into — at that point the link button switches itself off and says so, rather than handing you a link that opens an empty page. The ledger itself is unaffected: it stays in the address bar, a reload still brings it back, and "Copy as text" still gives you all of it.

For a trip, one person keeping the ledger is completely fine, and it is why this page is a free tool rather than a signup form. A holiday ends. Somebody settles up, and the ledger has done its job.

One thing it is not for, and there is a sibling page that is: the rent. A trip ledger is a pile of one-off receipts between changing subsets of people, and the rent is one standing number that repeats every month and divides the same way each time. If what you are dividing is rent, bills and unequal bedrooms, start on the rent splitter and come back here for the month's receipts.

It stops being fine when the expenses never stop. Housemates, couples, and especially separated parents are not settling up a trip — they are running an account that stays open for years, and the person keeping the ledger is doing unpaid administrative work that the others cannot see and therefore do not credit. That is the real cost, and no amount of copy-as-text fixes it.

You have outgrown this page when you notice three things at once: you are the only one who knows the current balance, you are retyping the same recurring bills every month, and somebody has started querying an expense from six weeks ago that you can no longer evidence.

That is the job the Expense Splitter app does. Everyone logs their own expenses into one shared ledger, so there is no bookkeeper; receipts attach to the expense that needs them; and a reimbursement between two people is something both sides sign off, which means the record of what was agreed survives the disagreement about it. For separated parents that countersigned record is usually the reason they came looking.

• Expense Splitter
• Trip Planner
• Co-Parenting

Every app in the library is included with the household plan. This page stays free either way.

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• Splitting the kids' expenses between two households without fighting
• What information should co-parents share, and what should remain private?
• Split rent and bills between housemates
• Work out what your subscriptions really cost in a year
• See a custody schedule on a calendar, and count the overnights
• Make a printable chore chart for your family
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