Rent is usually the biggest shared expense in a cohabitating relationship. It's also the one couples are most likely to handle incorrectly — either through a rigid 50/50 split that ignores income differences, or through a vague agreement that creates confusion month after month.
Here are three models, how to calculate each one, and what to document in your cohabitation agreement.
Model 1: Strict 50/50
How it works: Total rent divided by 2. Both partners pay exactly the same amount.
Best for: Couples with similar incomes, or couples who strongly prefer simplicity over perceived fairness.
Example: Rent is $2,400/month. Each partner pays $1,200.
The risk: If incomes diverge significantly, the lower earner pays a disproportionately high percentage of their take-home. Over time this tends to create quiet resentment — not necessarily stated, but felt.
Model 2: Income-proportional split
How it works: Each partner pays a percentage of total rent equal to their share of combined household income.
The formula: - Partner A income: $60,000 → 60% of combined - Partner B income: $40,000 → 40% of combined - Total rent: $2,400 - Partner A pays: $1,440 | Partner B pays: $960
Best for: Couples with a meaningful income gap who want the split to reflect financial reality.
The risk: Requires ongoing transparency about income, which some couples aren't comfortable with. Can also feel infantilizing to the lower earner.
Model 3: Room and use basis
How it works: If one partner uses more space — a dedicated home office, a larger bedroom — they pay more. The difference reflects actual use, not income.
Best for: Situations where space use is genuinely unequal.
Example: Partner A works from home and uses a bedroom as an office. They pay an extra $200/month to reflect that use.
What to put in writing
Whichever model you choose, document:
- The exact split (not "roughly equal" — the actual dollar amounts or percentages)
- The payment mechanism (individual transfers, shared account, one person pays landlord)
- What happens if either partner's income changes significantly
- Whether the split is reviewed periodically (annually, or when income changes by more than X%)
- What happens if one partner can't pay one month
That last item — the safety net conversation — is the one most couples skip. Decide now, while both of you can afford to be generous.
Document your rent split in a cohabitation agreement → Our free generator covers rent, utilities, shared expenses, and everything else in about 5 minutes.