The Roommate Rent Split Calculator divides total rent among roommates proportional to room size in square feet — the simplest defensible 'fair share' approach. A 1,000 sqft 3-bedroom apartment with bedrooms of 150, 120, and 100 sqft (370 total bedroom sqft) means roommate A's share is 150/370 = 40.5% of rent, B = 32.4%, C = 27%. For $3,000 total rent: A pays $1,216, B pays $973, C pays $811. Calculator handles 3-bedroom setups; for 2 or 4+ bedrooms apply the same proportional logic.
Common fairness factors beyond pure square footage: (1) En-suite bathroom premium — having private bathroom typically adds 10–20% to that room's share. (2) Walk-in closet vs reach-in — 5% adjustment. (3) View/window quality — 5–10% for premium views. (4) Parking spot ownership — usually allocated separately as add-on. (5) Utilities — split evenly or proportional to room share. (6) Common space access (does anyone get exclusive use of office or den?).
Alternative splitting methods: (1) Pure equal split — simplest but unfair when room sizes differ significantly. Works for similar-sized bedrooms only. (2) Square footage proportional (this calculator's default) — defensible and easy to explain. (3) Custom weighted — apply weights to bathroom access, parking, closet, etc. for finest accuracy but harder to negotiate. (4) Bid-based (Spliddit.org method) — each roommate states what they'd pay for each room; algorithm assigns rooms and payments. Used by roommate-matching services to eliminate ambiguity.
Distinct from rent splitting: utility and bill splitting. Most households split utilities (electric, gas, internet) evenly regardless of room size — usage tends to even out. Internet ($60–120) and streaming services ($20–50) typically split evenly. Groceries split based on actual usage (chore charts, shared shopping budgets, or just don't share groceries). Best practice: written roommate agreement covering rent split, utility split, chore allocation, guest policies, lease termination protocols. Splitwise app handles shared expense tracking; Rocket Lawyer has templates for formal roommate agreements.
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