Shared Rent Split Calculator

Work out shared rent split instantly with clear inputs, formula shown and shareable results.

About Shared Rent Split Calculator

A fair house share splits rent in two parts: bedroom space, allocated by area, and common areas — kitchen, bathroom, living room — split equally since everyone uses them the same. Putting 30-50% of rent in the common pool stops the smallest room paying almost nothing.

Formula

Rent split

my rent = (rent x (1 - common%)) x (my area / total bedroom area) + (rent x common%) / housemates

Worked example

With the default values below, Shared Rent Split Calculator returns My rent of $632.73. Change any input above and every figure here is recalculated in your browser.

Inputs used

Total monthly rent: 1,800
My room area: 16 m²
All bedroom area combined: 44 m²
Common area split share: 40 %

Results

My rent: $632.73
Room-based component: $392.73
Equal share of common areas: $240.00
Difference from an even split: $32.73

Step by step

1Values used
2Rent split
3My rent= 632.73
4Room-based component= 392.73
5Equal share of common areas= 240.00
6Difference from an even split= 32.73

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why not split purely by room size?

Because most of a flat is shared. Pure area splitting would have the person in the box room paying a quarter of the rent while using the same kitchen.

What else should adjust the split?

An en-suite, a balcony, better light or a parking space. Agree a small premium rather than arguing later.