Most couples start with fifty-fifty because it is obvious and feels even-handed. It works fine while you earn roughly the same, and quietly stops being fair the moment you do not — because an equal amount is a very unequal share of what each person has. Working out how to split expenses as a couple on different incomes takes about ten minutes and removes a resentment that otherwise builds for years. Our couples budget spreadsheet has the split calculator built in.
Having this conversation soon? Open the couples budget spreadsheet, put both take-home figures in, and let it do the percentages rather than arguing about them.
Shop Bill Payment Tracker →Why 50/50 Stops Being Fair
Take a couple with £2,400 and £1,600 take-home, and £1,800 of shared bills.
| Earns | Pays (50/50) | Left over | |
|---|---|---|---|
| Partner A | £2,400 | £900 | £1,500 |
| Partner B | £1,600 | £900 | £700 |
Both paid the same. But A keeps 63% of their income and B keeps 44%. In practice that means one of them can absorb a car repair and the other cannot, one can say yes to a weekend away and the other has to think about it. Over a few years that becomes a genuine imbalance in freedom, not just in money — and it rarely gets discussed, because on paper it looks scrupulously fair.
The Proportional Split
Each person contributes the same percentage of their income instead of the same amount. Three steps:
- Add both take-home incomes. £2,400 + £1,600 = £4,000.
- Divide each by the total. 2,400 ÷ 4,000 = 60%. 1,600 ÷ 4,000 = 40%.
- Apply to shared bills. £1,800 × 60% = £1,080 for A, £720 for B.
| Earns | Pays (60/40) | Left over | |
|---|---|---|---|
| Partner A | £2,400 | £1,080 | £1,320 (55%) |
| Partner B | £1,600 | £720 | £880 (55%) |
Now both keep the same proportion. Neither is subsidising the other; they are contributing equally relative to what they have.
Use take-home, not salary
Gross pay hides tax bands, pension contributions and student loan repayments. Two people on paper-similar salaries can have noticeably different amounts actually arriving, and the split should reflect what lands in the account.
Count all the income
Include everything that reliably arrives — benefits, maintenance, regular freelance work. Leaving out a real income stream skews the percentages and tends to feel unfair to whoever declared theirs fully.
Shop Expense Tracker →What to Still Split Evenly
Proportional splitting suits obligations — rent, energy, council tax, food, the things that exist whether you enjoy them or not. It suits choices less well.
Many couples run bills proportionally and keep gifts, holidays and meals out down the middle, on the grounds that both chose them equally. Others put a fixed amount each into a joint pot for those. Either works; what does not work is applying percentages to everything, which turns every dinner into an accounting exercise.
- Proportional: rent or mortgage, utilities, council tax, insurance, groceries, childcare.
- Even, or from a shared pot: holidays, gifts, meals out, joint treats.
- Entirely personal: clothes, hobbies, phone, individual subscriptions.
That third line matters as much as the first. Both partners keeping money that nobody has to justify is what stops a fair system feeling like supervision.
Making It Practical
The mechanics are simpler than the maths. Open a shared account for bills only. Both pay their share in on payday by standing order. Every household direct debit leaves from that account. Personal spending stays in personal accounts, unexamined.
That structure removes almost all of the friction, because nobody is chasing anybody for half of an energy bill. It also makes the system self-correcting: if the shared account runs short, the contribution amounts are wrong, and you find out within a month rather than after a year of one person quietly topping it up.
Work out the total first, before the percentages. List every genuinely shared cost — rent or mortgage, energy, water, council tax, broadband, insurance, groceries, childcare, any subscription you both use — and add them. Most couples are surprised by the figure, and it is worth seeing plainly before deciding who pays what. Anything either of you would keep paying if you lived alone and separately is personal, not shared, and does not belong in the calculation. A bill payment tracker on the fridge covers what leaves and when, and the expense tracker handles the shared spending that is not a direct debit.
Redo it when pay changes
A split worked out three pay rises ago is not the split you agreed to. Recalculate whenever either income moves meaningfully, and otherwise once a year — putting it next to something you already do, like a renewal, means it actually happens.
If you are combining finances for the first time, our guide to how couples should split bills covers the joint-versus-separate question in more depth, and the budget and finance binder or the finance bundle cover the household budget around it.
Shop Budget & Finance Planner →The Awkward Cases
The maths is easy. These are the situations where couples actually get stuck.
One of you has debt. Proportional splitting uses income, not what is left after repayments — otherwise the person with debt contributes less because of it, which tends to breed resentment. Most couples split on income and treat debt as personal, while agreeing it is a shared priority to clear. Our debt-free date guide is worth doing together.
One of you has stopped earning. Parental leave, illness, study, redundancy. Percentages break down at zero, and this is the point to stop splitting and start pooling: all income in, all bills out, an equal personal allowance each. The alternative — one partner asking for money — corrodes things quickly.
One of you owns the home. If a partner moves into a house the other owns, rent is genuinely contested territory. Contributing toward a mortgage builds equity for one person only. Many couples handle it by paying toward bills and running costs but not the capital, and agreeing explicitly that no ownership is being acquired.
Very unequal incomes. At a large gap, strict proportional splitting can leave the lower earner contributing an amount so small it feels uncomfortable. Some couples set a floor; others move to pooling. Either is fine as long as it is chosen rather than drifted into.
Have the conversation once, properly
Sit down with both take-home figures, the real list of shared bills, and an hour. Deciding it once and writing it down beats renegotiating a bill at a time, which is how most couples end up doing it — and is where the resentment actually comes from, rather than from the numbers themselves.
Splitting Expenses FAQs
What is the fairest way to split expenses when incomes differ?
Proportionally — each person contributes the same percentage of their income rather than the same amount. On £40,000 and £25,000 that is roughly 62% and 38% of the shared bills, which leaves both with a similar proportion of their own money left over.
How do I work out the proportional split?
Add both incomes, then divide each person's income by that total. £2,400 and £1,600 take-home makes £4,000 combined, so the split is 60/40. Apply those percentages to the shared bills total.
Should we use take-home pay or gross salary?
Take-home, every time. Gross salary ignores tax, pension and student loan differences, which can shift the real gap considerably between two people on paper-similar salaries.
Do we need a joint account?
Not necessarily, but a shared bills account is much simpler than chasing transfers. Both pay in their share on payday, all household direct debits leave from it, and personal spending stays personal.
What should still be split evenly?
One-off treats you both chose equally, and anything where proportional splitting would feel like accounting rather than partnership. Many couples split bills proportionally and gifts or holidays down the middle.
How often should we redo the split?
Whenever either income changes meaningfully, and otherwise once a year. A split calculated three pay rises ago quietly stops being fair without anyone noticing.
Work out yours in ten minutes. Open the couples budget spreadsheet with the split calculator built in, or browse the full Budget & Finance collection.