How to Split Shared Expenses Fairly: Trips, Roommates, Couples

In short

In the end, each person comes down to one number: what they paid minus their share. Anyone above zero gets money back, anyone below zero pays. Settled that way, a group of n people needs at most n − 1 transfers instead of everyone paying everyone. Equal splits suit trips, shares suit groups with kids, and many couples split by income.

The basic rule: paid minus share

Every shared expense has two sides: who paid and who it was for. That gives each person a balance, their standing in the group:

Balance = everything they paid − everything that falls on them
A positive balance means they fronted money and get some back.
A negative balance means others paid for them, so they settle up.
All balances always add up to zero. If they don't, an expense or a share is missing.

Example: a week in a vacation rental, four people

Anna, Ben, Clara and David split everything equally. Anna paid for the rental, Ben for dinner out and the big grocery run, Clara for gas, David for nothing.

Person	Paid	Share	Balance
Anna	€600	€250	+€350
Ben	€300	€250	+€50
Clara	€100	€250	−€150
David	€0	€250	−€250
Total	€1,000	€1,000	€0

Settle up with few transfers

If every expense were settled on its own, everyone would owe every payer their share. In the example that's nine transfers, some going both ways: Anna owes Ben her share of dinner while Ben owes Anna his share of the rental.

Working from the balances cancels out that back and forth. Whoever is below zero pays whoever is above zero until everyone is at zero:

David pays Anna €250.
Clara pays Anna €100 and Ben €50.

Three transfers instead of nine, with the same result for everyone. The rule behind it: every transfer brings at least one person to zero, so n people never need more than n − 1 transfers.

Equal, by shares or by amounts?

Equally: the default for a rental, a rental car, the big grocery run.
By shares: a family with two kids might count as three shares, a couple as two. Also handy when someone was only there for half the days.
By percentage: for fixed agreements such as 60/40.
By exact amounts: when everyone ordered something different, like at a restaurant.
Adjustments: split equally, but whoever had the expensive wine adds €15.

The method matters less than agreeing up front. A first talk about "who drank how much" after the trip is rarely about the money.

Couples: 50/50 or by income?

If both earn about the same, 50/50 is simplest. If incomes are far apart, many couples split shared costs in proportion to take-home pay, so both keep a similar share of their own money.

Example	Take-home	Share	Of €1,500 fixed costs	Left
50/50: partner A	€3,000	50%	€750	€2,250
50/50: partner B	€2,000	50%	€750	€1,250
By income: partner A	€3,000	60%	€900	€2,100
By income: partner B	€2,000	40%	€600	€1,400

Split by income, both keep 70% of their take-home pay. Which is fair is up to the couple; there's no right or wrong. It helps to separate shared costs (rent, groceries, vacations) from personal spending (hobbies, clothes) and split only the shared ones.

Roommates: fixed costs and groceries

Fixed costs such as electricity and internet are the same every month. Simplest: one person pays by standing order, and it's split as a recurring expense.
Shared supplies (dish soap, toilet paper, coffee) get logged by whoever pays. Personal items stay out.
Settle up regularly, for example once a month. Small amounts piling up over a year turn into long discussions at move-out.
When someone moves in or out mid-month, split fixed costs by days.

Paying by GiroCode

In the euro area, a GiroCode (EPC QR code) is a QR code following a European Payments Council standard for SEPA transfers. It holds the name, IBAN, amount and reference. Many European banking apps read it via photo or scan transfer, which fills in the whole transfer; you only confirm it. No typing an IBAN means no typos.

For quick small amounts, PayPal links or cash are common too. What matters is marking debts as paid afterwards so nobody pays twice.

Common pitfalls

Forgotten expenses: log them right away while you still have the receipt.
Logged twice: happens when two people enter the same bill. One shared record everyone sees prevents it.
Foreign currency: convert at the rate of the day you paid, not the rate at the end of the trip.
Tips: spread them in proportion to the items when orders were very different, not equally.

As of October 23, 2026. The examples are rounded and made up.

The matching app

Settle up with Obolus

Obolus works exactly like this: you log who paid and for whom, and the app shows everyone their balance and suggests as few transfers as possible. For iPhone, iPad and Android.

Invite the group by link or QR code; everyone logs expenses and sees the same balance
Split equally, by amounts, percentages or shares, with adjustments
GiroCode for paying, summary as text, CSV or PDF
Obolus Plus: split receipts by item, any currency at the ECB rate, recurring expenses

More about Obolus

Frequently asked questions

What's the easiest way to split expenses in a group?

Work out for each person what they paid minus their share. Whoever is below zero pays whoever is above zero until everyone is at zero. That way n people need at most n − 1 transfers.

How many transfers does it take to settle up a group?

At most one fewer than the number of people, if you settle the balances rather than each expense. For four people, three at most, often fewer.

Should couples split costs 50/50 or by income?

With similar incomes, 50/50 is simplest. With a big gap, many couples split in proportion to take-home pay, for example 60/40 at €3,000 and €2,000. Both are fair when agreed up front.

What is a GiroCode?

A QR code following the European Payments Council standard for SEPA transfers. It holds the name, IBAN, amount and reference. Many European banking apps read it via photo or scan transfer, which fills in the transfer.

How do you split expenses in a foreign currency?

Convert each expense at the rate of the day it was paid, then split it. Obolus Plus does this with the daily rate of the European Central Bank.

Split expenses fairly