Rent Split Calculator
$
15%
Rooms
ft²
ft²
ft²
Even Split (for reference)$1,000.00
Room A — 46.0%$1,380.00
Room B — 30.0%$900.00
Room C — 24.0%$720.00
Splitting rent evenly feels unfair when bedrooms differ in size or some have a private bathroom. This calculator weights each room by its square footage, adds an optional premium for an ensuite bath, and divides the total rent in proportion to those weights so everyone pays a share that reflects what they actually get.
Formula
rentᵢ = total × weightᵢ / Σ weight, weightᵢ = sizeᵢ × (privateBath ? 1 + premium : 1)
- total
- Total monthly rent to divide
- sizeᵢ
- Square footage of room i
- premium
- Private-bathroom premium as a decimal
How it works
- Enter the total monthly rent and a private-bathroom premium, then add a row for each roommate with their room name and size in square feet.
- Each room gets a weight equal to its size, multiplied by one plus the premium if it has a private bath. The weights are summed.
- Each roommate pays the total rent times their share of the combined weight, so the individual rents always add up to the full rent.
Worked example
Two equal 150 sq ft rooms share $3,300, but one has a private bath with a 20% premium.
- Weights: ensuite = 150 × 1.20 = 180; other = 150 × 1 = 150; total = 330.
- Ensuite rent = 3,300 × 180 / 330 = $1,800.
- Other rent = 3,300 × 150 / 330 = $1,500.
The ensuite room pays $1,800 and the other pays $1,500.
Frequently asked questions
- Do the individual shares always add up to the total rent?
- Yes. Each share is a fraction of the total based on its weight, so summing every roommate share returns the full rent, aside from sub-cent rounding.
- How should I set the private-bathroom premium?
- There is no fixed rule; 10% to 25% is a common range. Pick a figure the household agrees feels fair for the convenience of a private bath, then apply it consistently.
- What if rooms are the same size and none has a private bath?
- With equal weights everyone pays the same amount, which matches the even-split figure shown for reference. The weighting only changes things when rooms differ.