Household Cost Divider
Split rent, utilities, and shared costs by space, income, and real usage.
Household Members
Housing Costs
Split Method
Complications
Split evenly across all members as monthly reserve
Your Fair Split
Add household members and click Calculate to see your split.
Or load a preset scenario below to explore how it works.
How to Reach a Fair Split
Start with the space
Measure each bedroom's floor area in square feet. Do not count walls, and do not try to measure shared areas like the kitchen or living room. Those get handled by usage estimates. If one room has a private bathroom or balcony, add that space too. The person with more private space usually pays more rent, but how much more depends on your household's values.
Add income honestly
Use gross annual income before taxes. The calculator does not verify anything, and the numbers stay in your browser. Income-proportional splitting means someone earning $60,000 pays twice what someone earning $30,000 pays, for the rent portion. Many households compromise: equal utilities (everyone uses wifi the same), proportional rent (ability to pay matters more for the big bill).
Account for real life
Guests use water, electricity, and patience. The guest surcharge is a simple way to acknowledge that without tracking every shower. Pet costs include food, litter, vet bills, and any pet rent your landlord charges. Irregular expenses like a broken dishwasher or move-out cleaning get smoothed into a monthly reserve so no one faces a surprise $400 bill.
Compare and negotiate
The comparison table shows each person's share under equal and income-proportional methods. Use the gap between them as a negotiation range. A blended split lets you land anywhere in between. The goal is not mathematical perfection. It is a split everyone can explain to friends without embarrassment.
Scenario: Three Roommates in a City Apartment
Maya, Jordan, and Sam rent a three-bedroom for $2,400. Maya has the master with a private bath (180 sq ft). Jordan has a standard room (120 sq ft). Sam has the small room (90 sq ft) but makes the most money at $72,000. Maya makes $48,000 and Jordan makes $36,000.
Under equal split, everyone pays $800 rent. Jordan struggles. Maya feels her bigger room is undervalued. Sam feels penalized for earning more.
Under pure income-proportional, Maya pays $960, Jordan pays $720, Sam pays $1,440. Sam rebels.
Under space-weighted blended 60% space / 40% income, Maya pays $1,008 (bigger room, middle income), Jordan pays $696 (small room, lowest income), Sam pays $696 (small room, highest income offsets). The group agrees this feels fair. Sam's income cap prevents the worst case. Maya's space premium rewards her bigger room. Jordan's small room and low income both get protection.
They add $20/month guest reserve (Maya's partner stays over weekends), $40/month pet reserve (Jordan's cat), and $67/month irregular reserve. Final monthly shares: Maya $1,135, Jordan $823, Sam $823. Everyone signs the agreement. Six months later, Sam gets a raise to $88,000. They reload the saved configuration, adjust one number, and recalculate in seconds.
What to Double-Check
- Gross income ignores taxes, debt payments, and support obligations. Two people with the same gross income can have very different available money.
- Room measurements are self-reported. Bring a tape measure, not a guess.
- The guest surcharge is an estimate, not a tracking system. For precise guest accounting, you need a separate agreement.
- Pet damage deposits often come out of the security deposit at move-out. Decide now whether the pet owner repays others or if everyone shared that risk.
- Irregular expenses are a guess. If you spend $200 one year and $2,000 the next, the reserve will be wrong. Review annually.
- This agreement is not a legal contract. It documents intent. For legal enforceability, consult local tenant law or a mediator.
Common Questions
Should we use income-proportional or equal splitting?
Equal splitting works when incomes are similar and everyone values fairness as sameness. Income-proportional fits when one person earns much more and you agree that ability to pay matters. Many couples blend both: equal for shared utilities, proportional for rent. Try both and discuss.
How do we measure private space fairly?
Measure the floor area of each bedroom and any private bathroom or closet. Do not count walls. Shared spaces (kitchen, living room, hallways) are split by usage estimate, not measured. If one room has a balcony or better view, agree on a premium percentage together.
What counts as an irregular expense?
Things that happen unpredictably or rarely: replacing a broken appliance, emergency plumbing, bulk supply runs, or move-out cleaning. Estimate your annual total and split it across 12 months so no one gets surprised by a big bill.
Can landlords refuse our split arrangement?
Most landlords only care that the full rent arrives on time. Some require each person on the lease. The agreement template helps you document who pays what, which protects everyone if someone moves out early. Check your lease terms.
What if someone's income changes mid-lease?
Save your current configuration, then adjust the income figure and recalculate. Many households review splits every 6 months or after tax season. The localStorage save and shareable URL make this easy to revisit.
SplitFair v1.2. Last updated early 2026. Calculations run entirely in your browser. No data leaves your device.
Part of hub2.day, a collection of practical household tools.