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Bills and IOUs


  1. What's the difference between a Bill and an IOU?
  2. How do I add a Bill or IOU where different people pay different amounts?
  3. Whoops, I accidently logged a payment that wasn't made. How can I remove it?
  4. How does Flatmin work out who owes who what?

What's the difference between a Bill and an IOU?

An IOU is between you and other flatmates, generally one-off costs. If you paid for pizza for a few of your flatmates, you'd add that as an IOU. Or maybe you and a couple of your flatmates share meals, if someone pays for the grocieres they could add it as an IOU.

A 'Bill' is a Flat bill. That is, something that is paid from a shared bank account, or part of the every day running of your flat. The Power, Internet, and TV bills all come into this category. These are things that everyone should be able to see being paid by the flat.

In the end, Bills and IOUs use the same system behind the scenes. So if you're not sure whether something is technically a Bill or an IOU, it doesn't really matter - just pick one and go with it!

How do I add a Bill or IOU where different people pay different amounts?

  1. Head over to Add a Bill (or Add an IOU).
  2. Enter the total amount (if you don't know it, leave it blank). Check (or uncheck) all of the flatmates that should pay part of the total.
  3. Work out what everyone should pay, and change each flatmate's amount accordingly.
  4. Hit "Add Bill" (or "Add IOU") and confirm everything looks right. All done!

Whoops, I accidently logged a payment that wasn't made. How can I remove it?

Just head over to your transaction log, which lists all the payments and bills you added. To get there, head over to the My Flat tab and click your name. Find the payment you made in error, click the 'cog' and hit "Remove". Flatmin will remove the payment, and adjust any amounts owed on respectively.

How does Flatmin work out who owes who what?

Magic. Just kidding... Behind the scenes, Flatmin runs an accounting-style engine made to work with multiple people. If you're keen for some detail, read on.

The simple version is that Flatmin works it out just how you'd work it out. If Jim owes you $20 for pizza, but you owe Jim $30 for petrol money... it works out that you owe Jim $10.

For the detailed version, think of it like a bunch of virtual bank-accounts, where you have an account with each person in your Flat. When the account is positive, it means the other person owes you money. When it's negative ("overdrawn"), it means you owe the other person money.

Every time you pay for something and charge someone (or send them money), it increases the balance in that 'bank account'. Every time they send you money, or charge you for something, it decreases the balance in that 'bank account'.

In the end, Flatmin ends up with a bunch of virtual transactions in the 'virtual bank accounts'. The sum of those transactions is the balance of your account, and determines whether you owe someone money, or if they owe you money.

Flatmin works exactly the same way between you and the Flat Account.