How to split expenses with friends fairly, and know who owes whom

A trip, a shared flat, a birthday dinner: splitting expenses with friends looks simple until several people pay, the amounts are small and nobody remembers who covered what. The problem is rarely the money. It's the tally nobody kept.

The short answer

Record each shared expense once, when it happens. Keep a running balance per person, not a list of receipts. And settle up now and then, rather than paying each thing back separately.

Three fair ways to split

There's no single right way. What matters is agreeing on one beforehand:

1. Equal shares. The simplest. It works when everyone uses roughly the same: a holiday rental, a shared food shop.
2. By what each person had. For dinners where one person ordered a salad and another the tasting menu. Fairer, but more work.
3. By income. Common for couples and some shared flats: each person contributes in proportion to what they earn. We cover it in managing money as a couple.

Whatever you choose, write it down. An agreement that only lives in everyone's memory isn't an agreement.

The usual mess

Shared costs get complicated for three reasons:

• Several people pay. Today you pay for fuel, tomorrow your friend pays for groceries, the next day someone else pays for dinner.
• The amounts are small. Nobody wants to chase 4 euros or dollars, but twenty lots of 4 is 80.
• It's recorded late. Leave it to the end of the trip and there'll be missing receipts and plenty of doubt.

A balance per person, not a list of receipts

The idea that simplifies everything is this: instead of remembering every expense, keep track of how much each person owes you, or how much you owe them. Each shared expense nudges that balance one way or the other. In the end, only one figure per person matters.

So instead of ten small transfers, you make one when it's time to settle.

How to do it in abacova

abacova has a debts and shared expenses section with a balance per person.

• When you pay: use Split a bill. Enter your share and the rest is recorded as what the others owe you.
• When someone else pays: use Someone paid for me. Your share is recorded as your expense, in its category, and as what you owe that person. No money leaves your accounts until you pay them back.
• Loans: if you lend someone money, or they lend it to you, that's recorded too, with its date.

Each entry shows who paid, and each person's balance is clear at a glance: green moves it your way, red against you.

Settling up: when someone pays you, or you pay them, record it person by person, in full or in part, from whichever account you use. The payment clears the oldest debts first and doesn't count as a second expense.

If a debt will never be paid: you can write it off. No money moves, but your records reflect what really happened.

The lesson debts between people walks through it step by step.

Trips and shared flats

For a trip or a flat, add a tag to every related expense: "Lisbon trip", "Flat on High Street". Tags group transactions across different categories, so at the end you see what the whole trip cost, food, transport and accommodation included. Why a tag works better than a category here is explained in Trip to Rome is not a category.

Frequently asked questions

Do my friends need to use the same app? Not for you to keep track: the balances live in your own records. If you want to share the same books, you can invite other people into your organization.

How often should we settle up? At the end of a trip, or once a month in a shared flat. What matters is that nobody builds up a large figure without knowing it.

What if someone only pays part back? Record the partial payment and that person's balance drops by that amount.

Can I dictate a shared expense? Not yet: splitting a bill between several people is recorded from the debts section. You can dictate a loan to one person.

Start today

Next time you cover a payment, record it there and then. Create your abacova account and try Split a bill with your next shared expense.