Most money disputes between roommates and couples are not about the amount. They are about a method nobody agreed on, applied inconsistently, and never written down. Fix the method and most of the arguments disappear with it.
In short
There is no single fair way to split a bill, only the method that fits the people involved, agreed before the money changes hands. An equal split is simplest and works when incomes and usage are close. An income-proportional split asks the higher earner to pay a larger share, which takes an honest conversation about pay but eases the strain on whoever earns less. An itemized split charges each person for what they actually used, which is the fairest option and the most work to maintain. Whichever you choose, settle up regularly, keep a shared written record, and agree on the method before you move in together or split a big bill, not after the first disagreement about it.
Start here
Splitting a bill down the middle feels fair because it is simple, and simplicity is genuinely worth something. But equal is only fair when the people involved are roughly equal in what they earn and what they use. Two flatmates on similar salaries who cook and shop together can split almost everything evenly and never think about it again. A graduate sharing a flat with someone five years into their career, or a couple where one person works and the other studies, is a different situation, and an even split can quietly become a source of strain for the person paying a bigger chunk of what they take home.
The goal is not to find one universally correct formula. It is to pick a method that both people can look at and agree makes sense, say out loud what it is, and use it consistently. That conversation is worth having early, ideally before you move in together or before the first big shared bill arrives, rather than after a disagreement forces it.
Three methods
Each of these is genuinely fair in the right circumstances, and genuinely unfair in the wrong ones. Read the honest pros and cons before choosing.
Every shared cost is divided by the number of people, regardless of who earns what or who used more of it. Rent, DEWA, internet and the weekly grocery run are each cut into equal parts.
Works well when
Incomes are similar, usage is similar, and the group wants the least amount of arithmetic possible.
Falls short when
One person earns significantly more or less, or one person is home all day using the electricity and water the other barely touches.
Each person pays the same percentage of their income rather than the same amount. If one person earns 70 percent of the household's combined income, they cover 70 percent of the shared bills, and the other person covers 30 percent. The math is simple once both incomes are on the table: add the two incomes together, divide each person's income by that total, and apply the resulting percentage to every shared cost.
Works well when
Incomes differ meaningfully and both people would rather the person earning more carry a larger share, so the lower earner is not stretched thin by a bill that costs the same for everyone.
Falls short when
One or both people are not comfortable disclosing what they earn. This method only works with an honest, sometimes uncomfortable conversation about income up front, and it needs revisiting whenever either income changes.
Rather than splitting a bill as one number, it is broken into what each person actually bought or used. A grocery receipt is split by which items belonged to whom, not by the total. A utility bill can be split unevenly if one person works from home and runs the air conditioning all day while the other is out for ten hours; the person using more can reasonably cover a larger share of that specific bill, even if everything else is split evenly.
Works well when
Usage genuinely differs, such as one person eating out mostly and the other cooking, or one person working from home and the other not. It is the most accurate method there is.
Falls short when
Nobody wants to itemize every receipt every week. It takes more effort to maintain than the other two, so it tends to work best for the bills where the gap in usage is large enough to be worth the extra admin.
Most households end up mixing these rather than picking one. Rent and internet split evenly, groceries itemized by receipt, and the electricity bill adjusted because one flatmate works from home. When you need to work out a specific bill on the spot, NetWorth+'s free split calculator does the arithmetic for equal, percentage and itemized splits in the browser, with nothing to sign up for and nothing stored.
Keep it fair over time
The method you choose matters less than how consistently you apply it. These habits are what keep any of the three methods above working month after month.
A balance left to grow for months is harder to remember and more uncomfortable to bring up. Settle weekly for small, frequent costs like groceries and takeout, and at least monthly for rent and utilities. Small, regular settlements stay easy; large, occasional ones start to feel like a confrontation.
Memory is unreliable and it is never unreliable in a neutral direction; everyone tends to remember paying more than they did. A shared written record, even a simple one, removes the guesswork and the disagreement about who covered what last time.
Decide how you will split bills before you move in together, or before a large one-off cost like furniture or a deposit, not in the middle of working out who owes what. A method chosen calmly, in advance, holds up far better than one improvised during a disagreement.
A running total in someone's head, scattered across a group chat, is where most disputes start. Keeping every split, settlement and balance in one shared tool, rather than in memory or messages, makes the numbers checkable rather than debatable. See our comparison of NetWorth+ against Splitwise if you are choosing between tracking apps.
Questions
Keep reading
Work out a split in the browser. No sign-up, nothing stored.
Read moreRent, DEWA and groceries split without a spreadsheet.
Read moreUneven splits and read-only sharing between two people.
Read moreHow NetWorth+ compares for tracking shared expenses.
Read moreSplit any way you like, settle when you like, and watch the balance count as part of your net worth instead of disappearing into a group chat.
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