# How to run a shared kitty without arguments

A shared kitty is the simplest way to share costs: everyone puts money in up front, and shared expenses come out of it. Flatmates call it the house fund, travellers call it the pot, but the problem is always the same. After a month nobody quite remembers who put in how much, what it was spent on, or why there is less left than everyone thought.

This guide works for a flat fund, the pot for a trip, a collection for a gift, or any group that pools money for a purpose.

## How a kitty works

A kitty has three parts, and it helps to keep them apart:

1. **Contributions.** Each person puts money in. A contribution is not an expense: the money still belongs to the group.
2. **Expenses.** What comes out of the kitty for something shared: groceries, bills, fuel on a road trip.
3. **Balance.** What is left. It should be exactly contributions minus expenses. If it does not match the money that is really there, something was not recorded.

When all three are written down in one place, the kitty explains itself and nobody has to ask.

## Agree on four things first

Most arguments about a kitty are not about money but about what was never discussed:

- **How much each person puts in.** Equal shares is easiest. If incomes are very different, some groups contribute in proportion to what each person earns. What matters is that it is written down.
- **What the kitty pays for.** For example: food and cleaning yes, nights out no. Anything not on the list is paid separately.
- **Who holds the money.** Cash in an envelope, one person's account or a joint account. Where it sits matters less than everyone being able to see the record.
- **When it gets topped up.** Once a month, or when the balance drops below a set amount.

## How to record it without getting lost

### One account for the kitty

Treat the kitty as its own account, even if it is physically an envelope or someone's bank account. That way its balance never mixes with anyone's personal money.

### Every contribution, with a name

Record each contribution as income into the kitty, saying who made it: "Ana, 100, October". If someone has not put in their share yet, it shows straight away.

### Every expense, on the day

Write each expense down the day it happens, with a clear description and a tag for what it was for: "groceries", "cleaning", "Sofia's gift". An expense written down at the end of the month is a guess; one written down on the day is a fact.

### Check the balance together

Once a month, compare the recorded balance with the money that is actually there. If they match, great. If not, find the missing expense before more pile up.

## What if the kitty holds two currencies?

It happens on trips, or anywhere people save in one currency and spend in another. Instead of converting everything into one, keep one balance per currency and store the exchange rate of the day with each movement. We cover it in detail in [how to keep track of shared money in two currencies](https://contamos.xyz/en/blog/shared-money-in-two-currencies).

## What to do with what is left

If the kitty had an end, like a trip, there will be a balance when it is over. The usual options are to pay it back in the same proportions it came in, roll it over to next month, or spend it on something for everyone. Any of them works, as long as you decide before you have to.

## Frequently asked questions

### Who should hold the kitty's money?

Whoever the group trusts and can reach easily. Where the money sits matters less than everyone being able to see the record of what went in and out.

### Is a contribution an expense?

No. A contribution moves money into the kitty, and it still belongs to the group. Only what the kitty pays for is an expense.

### Should we open a joint account for it?

It helps if you pay a lot by card, but it is not required. An envelope of cash or one person's account works too, as long as it is recorded as its own account.

## Doing it in Contamos

[Contamos](https://contamos.xyz/en) is a shared ledger for any group that shares money, and a kitty fits it as it is:

- you create a team and invite the others; every member sees the same numbers and [who recorded each transaction](https://contamos.xyz/en/docs/members-and-roles);
- one [account](https://contamos.xyz/en/docs/accounts-and-currencies) is the kitty, with a balance for each currency it holds;
- each contribution is income and each purchase is an expense, with [tags](https://contamos.xyz/en/docs/tags) showing where the money went;
- you can [export everything to CSV](https://contamos.xyz/en/docs/transactions-and-transfers) whenever someone asks for the numbers.

Contamos does not move money or work out who owes whom: with a kitty that question mostly disappears, because everyone pays from the same place. It is free to start, and the [quickstart](https://contamos.xyz/en/docs/quickstart) takes a few minutes.