The example flat
Three flatmates share a flat for Rs 90,000 a month. Room A is 180 sq ft with an attached bathroom, room B is 140 sq ft, and room C is 120 sq ft. Total bedroom space is 440 sq ft.
Method 1: split it equally
Everyone pays Rs 30,000. It’s simple, and fine when rooms are close in size. Here it means C pays the same as A for two-thirds of the space and no private bathroom, which is where arguments start.
Method 2: split by room size
Each person pays their room’s share of the total bedroom space: A pays 180/440, B 140/440, C 120/440.
| Room | Size | Share | Pays |
|---|---|---|---|
| A | 180 sq ft | 40.9% | Rs 36,819 |
| B | 140 sq ft | 31.8% | Rs 28,636 |
| C | 120 sq ft | 27.3% | Rs 24,545 |
This overcorrects a little: the kitchen, lounge and shared spaces are used equally, but this method charges for them by bedroom size too.
Method 3: shared space equally, rooms by size, then perks
The fairest version for most flats. Agree what part of the rent pays for shared space; 40% is a reasonable start. Split that equally, split the other 60% by room size, then add a premium for perks.
Shared space: Rs 36,000 split equally
40% of Rs 90,000 is Rs 36,000, so everyone pays Rs 12,000 for the kitchen, lounge and shared areas.
Rooms: Rs 54,000 by size
A pays Rs 22,091, B Rs 17,182 and C Rs 14,727. Running totals: A Rs 34,091, B Rs 29,182, C Rs 26,727.
Perks: attached bathroom
The flat agrees the attached bathroom is worth Rs 3,000 a month. A pays Rs 3,000 more; B and C each pay Rs 1,500 less.
| Room | Shared | Room size | Perk | Pays |
|---|---|---|---|---|
| A | Rs 12,000 | Rs 22,091 | + Rs 3,000 | Rs 37,091 |
| B | Rs 12,000 | Rs 17,182 | − Rs 1,500 | Rs 27,682 |
| C | Rs 12,000 | Rs 14,727 | − Rs 1,500 | Rs 25,227 |
The percentages and the perk price are a judgment call, not a formula. Agree them before anyone moves in, write them down, and use the same split every month. The rent split calculator runs all three methods with your own numbers.
Bills: equal, unless usage really differs
Internet and cooking gas are usually split equally. Electricity is too, unless one person runs an AC or heater all day; then split it by shares. Groceries depend on whether you cook together.
In Duesy, make a flat group, set the rent split once as the group’s default, and add rent and bills as monthly bills with a due day. Each month it pre-fills the split, reminds everyone before the due date, and shows who owes whom. More in splitting bills with roommates.
Questions
What is the fairest way to split rent with different room sizes?
Split the part of the rent that pays for shared space equally, split the rest by bedroom size, and add an agreed premium for perks like an attached bathroom. For a Rs 90,000 flat with rooms of 180, 140 and 120 sq ft, that gives roughly Rs 37,091, Rs 27,682 and Rs 25,227.
How much more should the master bedroom pay?
There’s no fixed rule. Price its extra space by size, then agree a monthly premium for perks such as an attached bathroom or balcony, and take that premium off the others equally.
Should bills be split the same way as rent?
Usually not. Bills such as internet and gas are used equally, so most flats split them equally, and split electricity by shares only when usage clearly differs.
How do we stop arguing about it every month?
Agree the method once, write it down, and use an app that applies the same split every month. In Duesy you set the default split once and every new bill pre-fills it.