How to split bills when your incomes are unequal

Q: How do you split bills when one person earns more?

Add both take-home incomes together, work out what percentage of that total each person earns, and apply those percentages to the shared bills. On $3,000 and $7,000 a month that is 30 and 70 per cent, so a $4,000 pot is $1,200 and $2,800. It is the standard answer and it works, as long as both people know it narrows the gap in spending money rather than removing it.

Q: Is a 50/50 split unfair if incomes are different?

It depends on the size of the gap, not on the principle. Within about fifteen per cent of each other, an even split is simpler and nobody notices. Beyond that it starts producing very different amounts of leftover money: on $3,000 and $7,000 with $4,000 of bills, an even split leaves one person $1,000 and the other $5,000, and no amount of goodwill makes that stop mattering.

Q: Should we use a joint account or settle up each month?

A joint account for the shared bills is less work and fewer arguments, because the money leaves before either person has spent it. Settling up monthly keeps finances separate but requires somebody to track every shared purchase, and that tracking is where these arrangements usually collapse. If you settle up, agree who logs what on the day it happens rather than reconstructing a month at a time.

Q: How often should we redo the split?

Recalculate whenever either income changes by more than about ten per cent, and otherwise look at it twice a year. Percentages set against last year's salaries quietly become wrong, and the person they now disadvantage usually says nothing for months. Put the review in the shared calendar so it is not one person's job to remember.

Everyone gives you the same percentage formula and stops. What decides whether the arrangement holds is what that formula leaves each of you with.

31 August 2026

One of you earns considerably more than the other. You have been splitting the bills down the middle since you moved in, because that was obviously the fair thing to do.

It has stopped feeling fair. Probably around the time one of you started checking the balance before suggesting dinner out, and the other one didn’t.

Almost every page about this gives you the same percentage formula and stops. The formula is right. What nobody tells you is what it actually produces, which is the part that decides whether the arrangement holds up.

There are three methods, and everyone knows two

Take a household earning $3,000 and $7,000 a month after tax, with $4,000 of shared bills. Rent, utilities, groceries, insurance.

Even. $2,000 each. The lower earner is left with $1,000 for the month, the higher earner with $5,000.
By income. They earn 30% and 70% of the household total, so they pay $1,200 and $2,800. Left over: $1,800 and $4,200.
Levelled. Work backwards from equal spending money. $10,000 in, $4,000 of bills, $6,000 to divide, so $3,000 each. The lower earner pays nothing and the higher earner pays all $4,000.

The third one exists, it is arithmetically the only genuinely equal option, and hardly anyone chooses it. That is worth understanding before you assume the second one is doing something it isn’t.

Splitting by income does not give you the same money to spend

This is the bit the calculators skip, and it causes more quiet resentment than the original 50/50 ever did.

A proportional split makes the contribution equal in effort. Both people hand over the same slice of their pay. But the money left afterwards is still in the same 30:70 ratio it started in, because that is what proportional means. $1,800 against $4,200.

Paying the same percentage does not leave you with the same money. It leaves you with the same percentage.

So one person is choosing between the dentist and a weekend away while the other is deciding which index fund. Both of them agreed to a fair system, and both of them are right about that. The system was fair about contributions and silent about outcomes.

None of which means proportional is wrong. It means you should pick it knowingly, and say the quiet part out loud when you do: we are equalising what we put in, and we accept that what we keep will still differ.

Picking the one that fits

The size of the gap does most of the deciding.

If your incomes are	Use	Because
Within ~15%	Even	The difference is rounding. Save yourself the spreadsheet.
15% to 60% apart	By income	Big enough to hurt, small enough that shares feel right
More than 60% apart	By income, or levelled	At this distance percentages still leave one person short
One income is zero	Levelled, or pool everything	A percentage of nothing is nothing

The other ledger, the one nobody writes down

Money is not the only thing being contributed, and in a lot of houses the person earning less is doing more of the unpaid work. School runs, appointments, the mental filing cabinet of what needs doing and when.

A purely financial split prices that at zero. Sometimes that is correct and both people are happy. Often it is the actual grievance wearing a money costume, which is why the bills conversation gets heated out of proportion to the sums involved.

If that sounds familiar, splitting the mental load is the conversation to have first. Adjusting percentages will not fix a labour problem, and it is much easier to agree on money once the other ledger is visible.

The split is the easy part

Deciding is one evening. What kills these arrangements is the month that follows.

Somebody buys the groceries. Somebody else pays the plumber in cash. The car insurance comes out of an account only one of you can see. By the twentieth, neither of you can reconstruct who has paid what, so the settle-up becomes a negotiation based on two unreliable memories, and the honest answer is usually that whoever cares less about money quietly loses.

What actually works

Log it the day it happens, not at the end of the month. Reconstruction is where the arguments come from.
One place both people can see, so nobody has to ask for a total.
Mark shared versus personal at the point of spending. Deciding in December whether October’s dinner was shared is not a factual exercise.

This is the same failure the guide to tracking spending walks through: the entering is the whole cost, and any system that needs a quiet twenty minutes gets skipped in week three.

Joint account, or settle up

Two ways to move the money once you have agreed the shares.

A joint account for shared bills. Each person’s agreed amount goes in by standing order on payday, and every shared bill comes out of it. The money is gone before either of you has had a chance to spend it, which removes almost all of the friction. Keep personal accounts alongside it.

Settling up monthly. You keep entirely separate finances and square the difference at the end of the month. More control, considerably more admin, and it only survives if the tracking above is genuinely happening.

If you are inclined toward the second because a joint account feels like a commitment you have not made yet, that is a real answer and worth saying plainly to each other. It is also worth knowing you are buying that separateness with about ten minutes a week, forever.

Set a date to redo it

Percentages calculated against last year’s salaries are wrong percentages. One of you gets a raise, one of you drops to four days, a bonus arrives, and the arrangement carries on as though nothing happened.

Recalculate whenever either take-home moves by more than about ten per cent. Otherwise put a review in the shared calendar twice a year, so it belongs to the household rather than to whichever of you is better at remembering things.

Write the agreement down somewhere you will both find it. Not because anyone is going to breach it, but because in eight months neither of you will remember whether groceries were in the shared pot.

Common questions

How do you split bills when one person earns more?+

Add both take-home incomes, work out each person’s share of the total, and apply those percentages to the bills. On $3,000 and $7,000 that is 30 and 70 per cent, so a $4,000 pot becomes $1,200 and $2,800. Know what it does, though: it narrows the gap in what each person has left, it does not close it.

Is a 50/50 split unfair if incomes are different?+

It depends on the size of the gap rather than the principle. Within about fifteen per cent of each other, even is simpler and nobody notices. Past that it starts producing wildly different leftovers: on $3,000 and $7,000 against $4,000 of bills, even leaves one person with $1,000 and the other with $5,000.

Should we use a joint account or settle up each month?+

A joint account for the shared bills is less work, because the money goes out before either of you has spent it. Settling up keeps things separate but needs somebody to track every shared purchase, and the tracking is where these arrangements actually die.

How often should we redo the split?+

Whenever either income moves by more than about ten per cent, and otherwise twice a year. Percentages set against last year’s salaries go quietly wrong, and the person they now disadvantage tends to say nothing for months.