How to split bills when one of you earns more

Two people, one apartment, $2,000 a month in rent. One earns $40,000 a year, the other earns $90,000. Splitting it down the middle means each pays $1,000, and on paper that is the definition of fair: same bill, same contribution.

Now look at what that $1,000 costs each of them. The person on $40,000 takes home about $3,333 a month before tax, so rent eats 30% of everything they earn. The person on $90,000 is on about $7,500 a month, so the same $1,000 costs them 13.3%. One of them has a little over $2,300 left for the entire rest of their life that month. The other has $6,500.

That is the argument, and it is not really about the money. It is that an even split quietly transfers strain from the person who can absorb it to the person who cannot, while looking even-handed on the surface. Nobody in the conversation is being unreasonable. The number is just measuring the wrong thing.

The three methods, honestly compared

There are really only three approaches in common use. Each has a case, and the case for the first one is stronger than proportional-split advocates usually admit.

1. Equal split

Each person pays half of every shared bill. Its real advantage is that it requires no disclosure and no maintenance: neither of you has to know what the other earns, nothing has to be recalculated when a salary changes, and there is no formula to argue about. For two people on comparable incomes it is simply correct, and reaching for anything more complicated is making work for yourself.

It breaks down exactly when the incomes diverge, and it breaks down worse the tighter the lower income is. At a small gap it is a rounding error. When one person is paying 30% of their income and the other 13%, it is the reason one of you feels broke every month and cannot explain why.

2. Proportional to income

Each person pays the share of the bill that matches their share of the couple's combined income. Add both incomes, work out what fraction each contributes, apply that fraction to the bill. On $40,000 and $90,000 the split is 30.8% and 69.2%.

The result is that the bill costs both people the same percentage of their own income, which is the closest thing to a definition of equal sacrifice. It needs both incomes to be known, and it needs revisiting when one changes. That is the entire cost of it.

3. Equal after essentials

Subtract a personal floor from each income first, then split the bill in proportion to whatever is left. The floor is meant to cover the costs that do not scale with earnings: a phone, transport, minimum debt payments, medication.

This is the most defensible of the three in principle and the hardest to agree on in practice, because you now have to negotiate the floor as well as the split, and the floor is where genuinely different ideas about money surface. It also shifts noticeably more onto the higher earner than plain proportional does, which surprises people. With a $1,500 floor each, our couple lands at $468 and $1,532 rather than $615 and $1,385.

The same couple, all three ways

Numbers on their own are abstract, so here is the whole thing in one place. The last column is the one that matters: what the bill actually costs each person relative to what they earn.

Read the bottom two rows against the top one. Moving from equal to proportional does not take money from anyone in the sense that matters: it equalises what the month costs each of you. Moving again to the essentials method deliberately overshoots, so the higher earner now carries the larger relative load as well as the larger amount. Whether that is right depends on how much of the lower income is already committed before rent is paid.

The objections, taken seriously

Every one of these gets raised, and none of them is a bad-faith argument. Two of them are good enough to change what you should do.

“I do not want to tell anyone what I earn”

Reasonable, and more common than people admit, particularly early in a relationship or when one income is irregular. But notice that proportional splitting does not actually need the number to be spoken aloud. It needs the ratio. Two people can agree on "you cover 70%, I cover 30%" without either figure ever being said, and revisit it when something changes.

This is also why Halvy's income split stores a percentage and shows a percentage. The app never displays either salary to the other person, and there is an option to keep the exact figure hidden from yourself on the shared screens too. If disclosure is the blocker, agree on a ratio and move on.

“Our incomes change constantly”

Freelance, commission, shift work, seasonal. Recalculating monthly is miserable and it makes every fluctuation a conversation about money. Two things that work:

• Set the ratio from a trailing average, three to six months, and review it on a fixed schedule rather than whenever someone has a bad month. Quarterly is plenty.
• Only revisit it past a threshold. Agree up front that the split changes when someone's income moves by more than, say, 15%. Below that you leave it alone. This is the single change that stops the method becoming a chore.

“What about debt, and what about dependants?”

This is the objection that genuinely defeats plain proportional splitting. Gross income says nothing about a student loan, a car payment, child support, or medical costs, and two people on identical salaries can have very different amounts of actual freedom. If one of you is carrying significant fixed obligations, the essentials method exists precisely for this, and the floor is where you account for it.

How to actually run it month to month

The method is the easy part. What breaks is the admin, because an uneven split turns every shared purchase into a small arithmetic problem, and mental arithmetic is where resentment comes from. Four steps that hold up:

• Agree the ratio once, out loud. Write it down somewhere you will both see it. "60/40" ends more arguments than any spreadsheet.
• Decide what is shared. Rent, utilities, groceries, and the internet, typically. Personal spending stays personal. Do not proportionally split someone's own hobby.
• Let one person pay and settle up after. Splitting every individual transaction at the register is a bad use of your life. Whoever is standing there pays, it gets logged, and you square up once a month.
• Review on a date, not on a feeling. Put a recurring reminder in for the ratio review. It stops the topic being something one of you has to raise.

That third point is the one people underestimate. The reason even splitting persists despite being wrong for unequal incomes is that halving a number is easy and applying 30.8% to it in your head is not. Fix the arithmetic and the fair method stops being the inconvenient one.

One thing to settle separately if it applies: income is not the only unequal thing in a household. If the bedrooms differ too, do that split first so everyone agrees what each room is worth, then weight the result by income as a visible second step. How to split rent when the bedrooms aren’t equal has that arithmetic, and how to split shared costs fairly covers which method suits which cost.

If one income changes month to month, see how to split bills with irregular income for a monthly-versus-average comparison and a plan for quiet months.

Common questions

General information about shared household budgeting, not financial advice. Figures are illustrative and use gross monthly income before tax.