Fair Rent Split Calculator

Rent splitting between roommates can be done equally (simplest) or proportionally based on room size, amenities, or personal income. Different methods produce very different results, and it’s important to agree on the method before signing a lease.

Method 1. Equal split: Each Person’s Share = Total Rent ÷ Number of Roommates

Method 2. By room square footage: Person A’s Share = (Room A sq ft ÷ Total Living Space sq ft) × Total Rent

Method 3. By income (ability-to-pay method): Person A’s Share = (Person A’s Income ÷ Total Combined Income) × Total Rent

Method 4. Hybrid (room size + amenity premium): Add a fixed dollar premium for rooms with private bathrooms, better views, larger closets, etc., then split the remaining rent by room size.

Adjusted rent formula: Base Rent = Total Rent − All Premiums Person A’s Base Share = (Room A sq ft ÷ Total sq ft) × Base Rent Person A’s Total = Base Share + Applicable Premium

Where:

• Total Rent: the full monthly lease amount (not including utilities)
• Room sq ft: the area of each private bedroom only, or entire livable area if applicable
• Premium: a negotiated flat amount for superior features (en-suite bath, parking, balcony access)
• Shared spaces: common areas (kitchen, living room, bathrooms) are typically excluded from the room-size calculation since everyone uses them equally

Reference: typical room premiums. These are US dollar figures and only a starting point for the conversation; what matters is that the housemates agree on the number, not that it matches a table.

• Private en-suite bathroom: $50–$200/month premium
• Larger room (50%+ bigger): $100–$300/month premium
• Parking space: $50–$150/month
• Private balcony or patio: $50–$100/month

Worked example: 3-bedroom apartment, $2,400/month rent. Room sizes: 180 sq ft, 150 sq ft, 120 sq ft. Room 1 has a private bathroom (agree on $150 premium).

• Total room area = 180 + 150 + 120 = 450 sq ft
• Base rent after premium = $2,400 − $150 = $2,250
• Room 1 share = (180÷450) × $2,250 + $150 = $900 + $150 = $1,050
• Room 2 share = (150÷450) × $2,250 = $750
• Room 3 share = (120÷450) × $2,250 = $600
• Check: $1,050 + $750 + $600 = $2,400 ✓

Which method the calculator uses. It runs Method 4, the hybrid, and shows you Method 1 alongside it for comparison. Leave every premium at zero and Method 4 collapses into Method 2, the plain square-footage split, so you get that for free. Method 3, splitting by income, is not built in on purpose: it needs everyone to disclose their salary to their roommates, and in practice that conversation goes badly more often than it goes well.

A word on the premium itself. It comes off the top before anything is divided, which means the person with the en-suite pays the whole $150 and nobody else contributes to it. That is the point. If you instead added $150 to their share after the area split, you would be charging them for a premium on a base that already reflected their larger room, and the numbers would stop adding up to the rent.