How to Split Rent Fairly With a Roommate (The 4-Step Math)

Splitting rent 50/50 sounds fair, until one person has the big bedroom and the other is squeezed into the small one.

A fairer way is to split rent by the space each person actually gets. Here's the math in four steps.

The example

• Total rent: $3,500 a month
• Room 1: 375 square feet
• Room 2: 225 square feet
• Shared space (kitchen, living room, halls): 450 square feet

Step 1: Split the shared space

The kitchen, living room and halls belong to everyone, so split them evenly: 450 / 2 = 225 square feet each.

Step 2: Add it to each room

Your room plus your half of the shared space:

• Room 1: 375 + 225 = 600 square feet
• Room 2: 225 + 225 = 450 square feet

600 + 450 = 1,050. Every square foot is counted.

Step 3: Find each share

Divide each person's total by the size of the whole apartment:

• Room 1: 600 / 1,050 = about 57%
• Room 2: 450 / 1,050 = about 43%

Step 4: Multiply by the rent

• Room 1 pays $3,500 x 600/1,050 = $2,000
• Room 2 pays $3,500 x 450/1,050 = $1,500

Tip: use the exact fraction, not the rounded percentage, so the two shares add up to the full rent.

Then talk it through

The math gets you close. A conversation gets you to fair.

• Private bathroom? It's worth more. Adjust the split.
• Better closet, more light or a parking spot? Those count too.
• Utilities: split them evenly or by the same percentages. Just agree up front.
• Put it in writing. A simple roommate agreement prevents most fights later.

The takeaway

Bigger room, bigger share. A clear method and an honest conversation keep the money (and the friendship) in good shape.

Want a simple place to start? Grab our free zero-based budget template, and follow @press4please for more simple money lessons.

Example for illustration only. Not professional or legal advice.