How to Split Expenses as a Couple

Method 1: Split 50/50

Each partner pays half of every shared expense: rent, utilities, groceries. Simple to run and feels symmetric.

Best when incomes are similar. With a large income gap, 50/50 leaves the lower earner with far less discretionary money, which is the most common source of friction.

Method 2: Splitting bills based on income

Each partner pays the share of expenses that matches their share of the combined income. The calculation:

That is the whole "split bills by income calculator": divide, then multiply each shared bill (or the monthly total) by the percentage. Recompute when either income changes.

Best when incomes differ meaningfully; both partners keep a comparable share of their own income after bills.

Method 3: Assigned bills

Instead of splitting each bill, each partner owns whole bills: one pays rent, the other covers utilities, groceries, and insurance. Balance the assignments so each side roughly matches the split you want (equal or income-based).

Best when you want zero monthly settling-up. The risk is drift: bill amounts change, so compare totals every few months.

Making it work when living together

• Define "shared" explicitly. Rent and groceries usually are; personal subscriptions and hobbies usually are not.
• Track as you go. Log each shared expense when it happens; reconstructing a month from memory is where arguments start.
• Settle on a schedule. One transfer at the end of the month, whoever is behind pays the difference.
• Revisit yearly or when income changes. A method that fit as roommates may not fit after a raise or a career break.

ZenExpenses splits handle the bookkeeping: log who paid, choose equal or share-based splitting per expense, and see who owes whom.