Rent Split by Room Size Calculator

About this calculator

Splitting rent evenly among roommates ignores the fact that rooms are rarely the same size, so this calculator instead divides the total rent proportionally by each room's square footage: each roommate's share equals (their room's area ÷ total area of all rooms) × total rent. A tenant with a 200 sq ft room in a 600 sq ft three-bedroom apartment would pay one-third of the rent, while someone in a smaller 100 sq ft room pays proportionally less.

This area-based method is one of the most commonly recommended approaches (alongside the “bedroom fairness” and “market-rate” methods) for roommates negotiating a lease, since it's transparent, easy to justify with a tape measure, and avoids arguments about who “deserves” the bigger room.

New roommates signing a shared lease, landlords helping tenants split a master invoice, and subletters use it to agree on a fair number before move-in day, entering the total rent and each room's dimensions or area to get an itemized split.