Splitting Expenses With Unequal Incomes: 3 Worked Examples
Three real-feeling households with small, medium and large income gaps, with every split calculated so you can see which method suits your numbers.
The fairest way to split expenses with unequal incomes depends on the size of the gap. With a small gap, splitting 50/50 costs the lower earner very little. With a moderate gap, a proportional split usually works. With a large gap, especially after one partner cuts their hours, couples often protect a personal allowance for both first. The three examples below show each case with the arithmetic in full.
The methods themselves are explained in how to split bills when you earn different amounts. Here the point is to watch them work on households that look like real ones, with different costs and different pressures. Find the one closest to yours and start there.
Example 1: a small gap (Priya and Tom)
When incomes are within roughly a tenth of each other, 50/50 and proportional give almost the same result, so pick whichever is simpler.
Priya takes home £2,600 a month and Tom £2,400. They rent a one-bedroom flat with no children.
- Rent: £1,100
- Council tax, energy and water: £300
- Food and household shopping: £450
- Broadband, streaming, insurance: £150
- Total shared: £2,000
Combined income is £5,000, so Priya's share is £2,600 ÷ £5,000 = 52% and Tom's is 48%.
| Method | Priya pays | Tom pays | Left over |
|---|---|---|---|
| 50/50 | £1,000 | £1,000 | £1,600 / £1,400 |
| Proportional (52/48) | £1,040 | £960 | £1,560 / £1,440 |
The difference between the two methods is £40 a month. Either is defensible. What matters more for Priya and Tom is agreeing that they will revisit the split if one of them changes job, because a small gap can become a large one quickly.
Example 2: a moderate gap with a mortgage (Sam and Alex)
When one partner earns about twice as much, 50/50 starts to squeeze the lower earner, and proportional or equal remainder is fairer.
Sam takes home £4,000 a month and Alex £2,000. They own a small house together and run one car.
- Mortgage: £1,350
- Council tax, energy, water, broadband: £450
- Food and household shopping: £600
- Car (insurance, fuel, maintenance fund): £300
- Total shared: £2,700
Combined income is £6,000. Sam's share is £4,000 ÷ £6,000, which is two thirds; Alex's is one third.
For the equal remainder method, they each protect £500 of personal money first. That leaves Sam £3,500 and Alex £1,500, a total of £5,000, and the costs are split in proportion to those amounts: Sam 70% (£3,500 ÷ £5,000), Alex 30%.
| Method | Sam pays | Alex pays | Left over |
|---|---|---|---|
| 50/50 | £1,350 | £1,350 | £2,650 / £650 |
| Proportional (2/3, 1/3) | £1,800 | £900 | £2,200 / £1,100 |
| Equal remainder (£500 protected) | £1,890 | £810 | £2,110 / £1,190 |
Under 50/50, Alex puts £1,350 of £2,000 into the house and lives on £650. That is the classic squeeze: Alex is not short of income in absolute terms, but almost everything Alex earns is spoken for, while Sam has room for both of them.
Proportional fixes most of it. Equal remainder goes slightly further and suits Alex if the car is mostly used for Sam's commute, or if Alex is saving towards something personal. Either is a reasonable choice. The step that matters is choosing it together. For the formula behind the proportional row, see the step-by-step proportional calculation.
Example 3: a large gap after a baby (Maya and Jordan)
When one partner earns several times more, often because the other has reduced their hours for childcare, a protected allowance or equal leftovers is usually the fairest option.
Jordan takes home £5,600 a month. Maya went back to work part-time after their daughter was born and takes home £1,400. They rent a two-bedroom flat.
- Rent: £1,600
- Council tax, energy, water, broadband: £400
- Food and household shopping: £700
- Nursery, two days a week: £500
- Nappies, clothes and other baby costs: £300
- Total shared: £3,500
Combined income is £7,000. Jordan's share is £5,600 ÷ £7,000 = 80%; Maya's is 20%.
For equal remainder they protect £500 each. That leaves £5,100 and £900, a total of £6,000. Jordan's share becomes £5,100 ÷ £6,000 = 85% and Maya's 15%.
For the residual method, the aim is identical amounts left. Combined income £7,000 minus £3,500 of costs leaves £3,500, so £1,750 each. Jordan pays £5,600 − £1,750 = £3,850, which covers all the costs plus a £350 transfer to Maya.
| Method | Jordan pays | Maya pays | Left over |
|---|---|---|---|
| 50/50 | £1,750 | £1,750 | £3,850 / −£350 |
| Proportional (80/20) | £2,800 | £700 | £2,800 / £700 |
| Equal remainder (£500 protected) | £2,975 | £525 | £2,625 / £875 |
| Residual (equal leftovers) | £3,850 | −£350 | £1,750 / £1,750 |
A 50/50 split is impossible here: Maya's share would be more than she earns. Proportional works on paper but leaves Maya £700 a month for everything personal, while she carries more of the childcare that made her income drop in the first place.
That last point is why many couples in this position choose equal remainder or residual. Maya's reduced pay is the result of a joint decision about their daughter, not a personal one. Some couples also agree that Jordan pays into Maya's pension during these years, since her contributions drop with her pay. That is worth discussing with a qualified financial adviser, because the right structure depends on your situation.
What do the three examples have in common?
In every case, the left-over column tells you more than the paid column. "We both pay half" sounds fair until you see that one person has £650 or minus £350 left.
- Small gap: the method barely matters. Choose for simplicity.
- Moderate gap: 50/50 starts to bite. Proportional is the usual answer.
- Large gap, especially from a joint decision such as childcare: protect personal money for both, or aim for equal leftovers.
The examples also leave out something that matters: who does the unpaid work. Maya likely carries more of the nursery runs, the night wakings and the mental load of a small child. That should be seen, but it belongs on a separate measure of time rather than folded into the money split. EvenUS keeps the two apart for exactly this reason.
How do you work out which example matches your household?
Divide the higher take-home pay by the lower one. Under about 1.2 is close to Example 1. Around 2 is Example 2. Three or more, or one partner earning very little, is Example 3.
Then check what the lower earner has left under your current split, and whether it covers a normal month with a little room to spare. If it does not, move one row down in the table. The household fairness calculator will run your own numbers, and the new parents guide covers more of what shifts in Maya and Jordan's situation.
Common questions
Should childcare costs be split proportionally?
Childcare for your shared children is usually easiest to treat as a household cost, split the same way as everything else. Some argue it should be shared differently because it enables one partner to work; either way, decide it explicitly rather than by default.
What if the higher earner has large personal debts?
Some couples subtract required debt repayments from income before calculating the split. Whether that is fair depends on when and why the debt arose, and for significant debt a free debt advice charity or adviser is a better guide than a formula.
How often should we change the split?
Recalculate when either income changes noticeably, and at least once a year. Example 3 would look different again once Maya goes back to full-time hours.
General information, not financial advice. The disclaimer says when to talk to a professional instead.