Rent Split Calculator
Split the rent fairly between flatmates: shared space per person, bedrooms by size. Advanced adds couples, room extras, bills and the deposit.
For any period: a month, a week or a year.
50% is a common starting point. This part (kitchen, living room, hallway) is split equally per person; the rest is split by bedroom size.
Tick them on each room above. A % makes the room count as that much bigger; a set amount is paid by that room on top and comes off what everyone shares.
How your rent is split
Shared space is split per person; the bedroom part is split by room size.
- 1
Share the common space
$3,000 × 50% ÷ 3
= $500 each - 2
Rooms by size
$1,500 × 160 ÷ 400
= $600 - 3
Room 1 pays
$500 + $600
= $1,100 - 4
Check against equal
$3,000 ÷ 3 = $1,000
+$100 more
Read more: the formula, a worked example and tips for a fair split
The formula
shared part per person = rent × shared % ÷ number of people
room part = rent × (100% − shared %) × room size ÷ all bedroom sizes
room pays = shared part × people in the room + room part
Room extras: a % extra makes that room count as that much bigger in the room part (size × (1 + extra %)). A set amount is paid by that room on top, and is taken off the rent before the rest is shared out, so the shares still add up to the rent.
Worked example
Rent of 3,000 for three bedrooms of 160, 120 and 120 ft², with 50% for shared space:
- Shared part: 3,000 × 50% = 1,500, and 1,500 ÷ 3 people = 500 each.
- Room part: the other 1,500 by size. All bedrooms add up to 160 + 120 + 120 = 400 ft². Room 1: 1,500 × 160 ÷ 400 = 600. Rooms 2 and 3: 1,500 × 120 ÷ 400 = 450 each.
- Room 1 pays 500 + 600 = 1,100; rooms 2 and 3 pay 500 + 450 = 950 each. 1,100 + 950 + 950 = 3,000.
- An equal split would be 3,000 ÷ 3 = 1,000 each, so Room 1 pays 100 more and the others 50 less.
- Per ft²: Room 1 pays 1,100 ÷ 160 = 6.88; rooms 2 and 3 pay 950 ÷ 120 = 7.92. Small rooms pay a little more per ft² because everyone pays the same for the shared space.
Choosing the shared-space %
| Shared % | When it fits | Example shares |
|---|---|---|
| 0% | Pay purely by bedroom size | 1,200 · 900 · 900 |
| 25% | Small kitchen, people mostly in their rooms | 1,150 · 925 · 925 |
| 50% | A common starting point | 1,100 · 950 · 950 |
| 75% | Big living space you all use | 1,050 · 975 · 975 |
| 100% | Equal split, size ignored | 1,000 · 1,000 · 1,000 |
Example shares use the worked example above (3,000 rent; rooms 160, 120 and 120 ft²).
Tips for a fair split
- Measure the bedrooms wall to wall. Built-in wardrobes count; an en-suite bathroom is better as an extra.
- Couples: set 2 people on their room. They then pay two shares of the shared space, and bills split per person count them twice.
- Extras: 10–20% for a private bathroom and around 5% for a balcony or AC are common choices, but agree them together.
- Write it down. Share the link so everyone sees the same numbers.
Common questions
What is the fairest way to split rent with flatmates?
Most people split the shared space (kitchen, living room, hallway) equally per person and the bedroom part by room size. With 3,000 rent, half for shared space and rooms of 160, 120 and 120 ft², each person pays 500 for shared space, and the bedrooms add 600, 450 and 450, so the shares are 1,100, 950 and 950.
What percentage of rent is common area?
There is no fixed rule. 50% is a common starting point. If the kitchen and living room are large and you all use them a lot, go higher (60–70%); if people mostly stay in their own rooms, go lower (30–40%). At 100% everyone pays the same; at 0% you pay purely by bedroom size.
How much more should a room with a private bathroom pay?
Flatmates often agree on 10–20% more for an en-suite bathroom, or a set amount. In Advanced, tick Bathroom on that room and set the extra as a % (the room counts as that much bigger) or as an amount paid on top, which comes off what everyone else pays.
Should a couple sharing a room pay more?
Usually yes. Two people use the kitchen, bathroom and bills twice as much, so this calculator gives a room with two people two shares of the shared space. You can add a Couple extra on top if you also want them to pay more for the room itself.
How should we split bills and the deposit?
Bills like electricity and internet are usually split per person, because that is how they are used. The deposit is often split in line with each person's rent, so whoever pays more rent puts in more. Both options are in Advanced.
Why does a small room cost more per square foot?
Because the shared space is split equally. Everyone pays the same for the kitchen and living room, so that fixed part counts for more of a small room's rent. That is normal: the small room still pays less in total.
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