How to Split a Couples Budget by Income: 3 Fair Methods, With the Math
When two people earn different amounts, splitting shared bills 50/50 can feel fair to one person and quietly painful to the other. There are three common ways to split, and putting real numbers next to each other makes the conversation much easier.
The example couple
Alex takes home $5,400 a month. Jordan takes home $3,600. Together that's $9,000. Their shared costs (rent, utilities, groceries, internet, shared subscriptions) come to $3,000 a month.
Three methods compared
| Method | Alex pays | Jordan pays | Alex keeps | Jordan keeps |
|---|---|---|---|---|
| 50/50 | $1,500 | $1,500 | $3,900 | $2,100 |
| Proportional to income (60/40) | $1,800 | $1,200 | $3,600 | $2,400 |
| Equal money left over | $2,400 | $600 | $3,000 | $3,000 |
50/50
Simple and easy to track. It works well when incomes are close. When they aren't, the lower earner's personal budget gets squeezed: here Jordan pays 42% of their income toward shared costs while Alex pays 28%.
Proportional to income
Each person pays the same percentage of their income. Alex earns 60% of the household total, so Alex covers 60% of shared costs. Both pay 33% of their take-home. This is the most common "fair" split, and it adjusts automatically when either income changes.
Equal money left over
Both people end up with the same personal spending money. It treats the household more like one pot and suits couples who already think of income as shared. It asks a lot of the higher earner, so both people should be genuinely happy with it.
The spreadsheet formulas
With Alex's income in B2, Jordan's in B3 and total shared costs in B5:
- Alex's share %:
=B2/(B2+B3)→ 60% - Alex pays:
=B5*B2/(B2+B3)→ $1,800 - Equal-leftover, Alex pays:
=(B2-B3+B5)/2→ $2,400. Jordan pays the rest:=B5-that.
Use take-home pay, not salary, in all of these. Pre-tax numbers overstate what the higher earner can actually spend.
Settling up when you both pay for things
Very few couples pay shared costs from one account in exactly the right proportions. Usually one person pays rent, the other does the grocery runs, and someone grabs the internet bill. So at the end of the month you compare what each person paid with what they should have paid:
| Paid this month | Fair share (60/40) | Difference | |
|---|---|---|---|
| Alex | $1,300 | $1,800 | −$500 |
| Jordan | $1,700 | $1,200 | +$500 |
Alex owes Jordan $500 for the month. One transfer, done. Keeping a running balance means you can settle monthly or whenever it gets big, without anyone keeping score in their head.
One extra rule saves a lot of arguments: personal spending counts 100% to the person it was for, whoever paid. If Jordan buys Alex's concert ticket on the shared card, it goes on Alex's side, not the shared pot.
Our Couples Shared Budget does exactly this: log who paid and who it was for, pick 50/50, income-based or a custom split, and the dashboard says who owes whom, for the month and year to date.
Making it work in real life
- Agree on what "shared" means before arguing about percentages. Is a gym membership shared? Gifts for each other's families?
- Give each person a no-questions personal allowance. Friction usually comes from small personal purchases, not rent.
- Check in monthly, briefly. Ten minutes with the dashboard beats a tense conversation every few months.
- Use one shared file. A Google Sheet both of you can edit removes the "I didn't know" problem.
General education only, not financial or legal advice. Figures in the tables are simple arithmetic on the example incomes.