Split rent by room size
Enter the monthly rent and each private room’s size to see what everyone pays.
1. Monthly rent
View splitExample values — change them to match your plans.
2. Room sizes
Enter each private room’s area. Leave shared spaces out. Names are optional.
Adjust contributions (optional)
Equal weights split rent by room size alone. Agree on any changes together: a higher weight increases that person’s share.
- Flatmate 1
- Flatmate 2
- Flatmate 3
Monthly rent per person
Updates as you type
- Flatmate 114 m² · 33.3% of rent
- €500.00
- Flatmate 214 m² · 33.3% of rent
- €500.00
- Flatmate 314 m² · 33.3% of rent
- €500.00
How this is calculated
- Rent€1,500.00
- Total private room area42 m²
Rounding is adjusted so the shares add up to the total rent.
What room size leaves out
This calculator assigns the whole rent by private room size. It excludes shared areas such as the kitchen and living room, which can make bedroom differences count for too much. It also leaves out features such as an en suite or better light.
If you want to account for shared space, agree on a portion of the rent to divide equally and divide the rest by bedroom size. You can record that calculation in a spreadsheet. An equal split may be enough when the rooms are similar.
Agree on the split before paying
Use the result as a starting point for your household’s agreement. Optional contribution weights multiply each room’s area. Save the amounts you agree on for each month.
Good to know
The official service is free to use and has no paid tier.
Automatic conversion for 156 currencies at the day’s indicative rate.
A room holds up to twenty people.
Split records payments. It does not send money or verify payments with a bank.
Track shared household expenses
Create a room and share the link with your flatmates. No account or download required.
Start a splitQuestions
- How do you split rent by room size?
- Divide each private room’s area by the total private room area, then multiply by the rent. The calculator uses this method by default. Shared areas are excluded, so consider whether you want to divide part of the rent equally to account for them.
- How do optional contribution weights work?
- Open “Adjust contributions” to set a weight from 1× to 5× for each person. The calculator multiplies each room’s area by its weight, then splits the rent in those proportions. Equal weights cancel out, so rent follows room size alone. If every room size is zero, the calculator starts with equal room shares.
- How do you split rent when one flatmate earns more?
- If everyone agrees that the higher earner should contribute more, open “Adjust contributions” and raise their weight. The calculator multiplies their room’s area by that weight. It does not use income figures. Leave all weights equal to split by room size alone.
- Why does one flatmate pay a fraction more than the others?
- Rounding can leave a small amount unallocated. The calculator rounds each share down, then distributes the remainder to the largest fractions, one smallest currency unit at a time. This keeps the total equal to the rent.