Split Rent Fairly Between Roommates
Use this rent split calculator to divide rent fairly between roommates — by income (proportional), by room size, or split evenly. Three methods to handle any housing situation.
How this calculator works
The fairest way to split rent depends on what you're optimizing for: equitable burden (everyone sacrifices the same share of disposable income), market fairness (you pay for what you use), or simplicity. Pick one method from the calculator above, or read below to choose.
Splitting rent by income (proportional method)
This is the most equitable approach when roommates earn very different amounts. Each person pays a fraction of rent equal to their share of the household's total income.
Use this method when one roommate makes 30%+ more or less than the others. A senior software engineer paying the same rent as a graduate student is a setup for resentment within six months.
Splitting rent by room size (square-footage method)
This is the market-fair approach when bedrooms are noticeably different — a master bedroom plus a small spare, or any layout with a private bathroom attached to one room. Each person pays in proportion to their room's square footage:
For a private en-suite bathroom, add a 10–15% premium to that room's effective square footage. Closet space, window count, and street-vs-courtyard view occasionally factor in too, but the rule of thumb is: stick to floor area unless one room is dramatically better in a measurable way.
Splitting rent evenly
Equal split works when bedrooms and incomes are all roughly comparable. It's the simplest and cheapest to administer — which is its own kind of fairness when nobody wants to negotiate.
The hybrid (mixed-method) split
For mixed scenarios — a roommate with both the bigger room AND the lower income — run the calculator twice: once by income, once by room size. Then average the two numbers, or apply weights (e.g., 70% income / 30% room size) that reflect what your group cares about most. This is what most informal spreadsheet-driven splits eventually converge on.
Sources: The math is basic proportional weighting — no regulatory authority sets rent-splitting rules between private parties. Tenant rights and lease co-signer rules vary by state; see HUD tenant rights. Review your lease to confirm whether all roommates are jointly liable for the full rent — most leases say yes, which means the split is a private agreement, not a legal one.