You’ve probably lived this. The flat’s WhatsApp group: “I’ll Bizum you later”, “did I pay you for the electricity?”, “I think I got Saturday’s groceries”. By the end of the month there are a dozen Bizum payments going back and forth, each one sitting in someone’s own banking app, and nobody knows who’s ahead. Someone suggests “let’s just call it even and start over”. Someone loses money without knowing it.
That’s the endless Bizum loop. And the problem isn’t Bizum.
(Bizum is Spain’s instant phone-to-phone payment system, built into almost every Spanish banking app.)
Bizum does one thing really well
It has 30.6 million users in Spain, and in 2025 it handled 1.237 billion transactions, around 3.4 million a day. It’s instant and almost everyone has it. For sending your flatmate her share of the electricity, nothing is easier.
But paying and keeping track are two very different things. Bizum is built for the first, and at home we use it for both.
Where it breaks
| What Bizum does | What it doesn’t do |
|---|---|
| Moves money instantly | Add up everything that happened in the month |
| Splits one expense between several people (a dinner, a gift) | Keep the balance of many expenses paid by different people |
| Keeps your history in your banking app | Show everyone else what you see |
| Carries a note | Know whether that expense was shared or just yours |
It’s true that Bizum can split: with a multiple request you can ask several people for their share of one expense at once. For a dinner it works beautifully. A flat’s problem isn’t one dinner, though: it’s thirty small expenses a month, each paid by whoever happened to be at the supermarket, crossed with the Bizums people send to even things out. No Bizum knows anything about the others.
Why it hurts more in a shared flat
In Spain, sharing a flat is no longer a phase, it’s how people manage to move out at all. According to the Spanish Youth Council’s 2025 Emancipation Observatory, renting alone eats 98.7% of a young person’s average salary. Sharing brings it down to 33.6%. It’s the only option where the numbers work.
And what gets shared isn’t small. According to Spain’s National Statistics Institute (INE) household budget survey, the average household spent €11,665 in 2025 on housing, water, electricity and gas: a third of everything it spends. That’s a lot of bills, a lot of shopping and a lot of people paying for different things.
The three workarounds that don’t last
1. Screenshots in the group chat. Everyone posts a photo of the receipt or the Bizum. A week later they're buried under memes and nobody adds them up.
2. The spreadsheet. It works for the first two months. Then one person ends up maintaining it and becomes the flat's accountant without ever asking to. We cover this in why spreadsheets can't keep up with shared expenses.
3. The splitting app where you have to log everything. Tricount or Splitwise do the maths well, but only with what someone types in by hand. One person forgets one expense and the balance lies.
Your bank statement already has it all
Here’s the part almost nobody mentions: all of it is already recorded. Every card payment at the supermarket, every electricity direct debit and every Bizum sent or received appears on your bank statement, with its date and amount. There’s nothing to log. You just have to bring it together once a month.
Download the statement
At the end of the month, everyone downloads their own.
Mark what's shared
Groceries, electricity, internet: shared. Your gym: yours.
Check the balance
Who put in more than their share, and who less.
One single Bizum
You settle with one or two payments, not twelve.
If you don’t live in Spain, the mechanism is exactly the same: swap Bizum for SPEI or CoDi in Mexico, Mercado Pago or an instant transfer in Argentina and Chile, or whatever payment app you use. Your payment app isn’t your ledger; your bank statement is.
An ordinary month, worked out
Worked example · Three people, one flat, one month
€357 of shared expenses · €119 per person
Marcos — electricity (€78), internet (€35) and one grocery run (€29.60). He's put in €142.60.
Lucía — two grocery runs (€64.30 and €38.90) and the cleaning supplies (€18). She's put in €121.20.
Nerea — the gas (€42) and one grocery run (€51.20). She's put in €93.20.
Mid-month — Nerea sent Lucía a €15 Bizum "for the shopping", and Lucía sent Marcos €26 "for the electricity".
Marcos is convinced he's the one who's owed. Put it all together and he isn't: Nerea owes Lucía €10.80 and Marcos owes Lucía €2.40. Two Bizums and the month is square. If you'd rather not split equally, we explain the options in how to split rent and utilities fairly.
That final twist is exactly what endless Bizums hide: the mid-month payments shift the balance, and nobody keeps them in their head.
How SameNest does it
SameNest is built around those four steps. Everyone uploads their own bank statement, whatever the bank (CSV, Excel or PDF), without connecting the account. SameNest sorts the movements, lets you mark what’s shared and what’s yours, and keeps the balance of who owes whom. When it’s time to settle, it takes one tap. You can see the plans and pricing: the first 30 days are free, no card needed.
No more endless Bizums
Upload your statement at the end of the month and SameNest tells you who owes whom. Nothing to log by hand.
In short
Bizum is the best way to pay and the worst way to keep track. You don’t need to stop using it: you need to stop asking it to be your ledger. The record already exists, on your bank statement. Bring it together once a month, mark what’s shared and settle with one Bizum. For the full cycle, from what counts as a shared expense to how to settle up, continue with the guide to shared household expenses.