How to split apartment bills fairly between flatmates

Sharing an apartment saves money — until the end of the month, when someone has to work out who owes what. Rent is easy. But add electricity, gas, water, Wi-Fi that only some people use, a shared meal pool, and the groceries someone bought out of pocket, and a simple split turns into an argument. This guide covers a fair, transparent method used by thousands of messes and shared flats.

1. Separate your costs into four buckets

Fixed costs — rent, gas, water, building service charge. Same every month.
Variable costs — electricity. Changes monthly, entered from the meter or bill.
Optional costs — Wi-Fi, house maid, satellite TV. Only some flatmates use them.
Meals & personal expenses — shared food shopping and things individuals bought for the flat.

Mixing these together is the number one cause of disputes. Splitting everything equally is only fair if everyone uses everything equally — and they never do.

2. Split fixed costs (with custom rent support)

The simple version: divide the fixed total by the number of flatmates. But real apartments often have one person in the small room paying less, or a couple paying more. The fair formula is:

Example. Rent + gas + water + service = ৳24,080 for 4 flatmates. Rafi has the small room and pays a fixed ৳4,500. The remaining ৳19,580 is split equally among the other 3 — ৳6,527 each.

3. Electricity: enter it once, then lock it

Electricity should be entered by one trusted person (the bill manager) when the bill arrives, split equally, and then locked so nobody can quietly change the numbers later. A locked month with a visible history is what keeps trust in the system.

4. Optional costs: only opt-ins pay

If two of five flatmates never use the house maid, they should not pay for her. List each optional cost, record who opted in, and divide that cost only among those members.

5. Meal costs: the per-meal rate

The standard mess formula:

Per-meal rate = total meal shopping ÷ total meals eaten

If the flat spent ৳18,000 on food and members ate 600 meals in total, the rate is ৳30. Someone who ate 80 meals owes ৳2,400; someone who ate 40 owes ৳1,200. Each person pays for exactly what they ate — tracked with a simple weekly checklist.

6. Settle personal expenses with carry-forward

When one flatmate buys cleaning supplies or pays the plumber from their own pocket, record it. At month end, compare what each person spent against the equal share — whoever spent more carries a credit into next month, whoever spent less carries a debt. Over a few months it evens out automatically, without awkward cash exchanges.

7. Put it all together

Each flatmate’s monthly bill is:

their share of the fixed bucket (respecting custom rent), plus
their equal share of electricity, plus
their share of each optional cost they opted into, plus
their meal count × the per-meal rate, plus or minus
expense carry-forward and any adjustments.

Doing this in a spreadsheet works — until someone forgets to update it, or two versions float around. The fix is a single shared source of truth that everyone can see but only the right people can edit.

LocalHost does all of this automatically — free for any apartment.

Start splitting bills fairly