How do we split bills fairly when one of us earns more?
There are three common ways: split everything 50/50, split by each person's share of the combined pay, or split so you both end up with the same amount left over. On the same pays and bills they give very different results for the lower earner. Fair is whichever one you both agree on and can explain, and it's worth running the numbers before you pick.
The short version
- The same $2,500 of bills leaves Alex with $350, $600 or $750 a fortnight depending on the method they choose.
- After the change, 50/50 no longer works at all, so Sam and Alex move to income share or equal leftover.
- For bills that aren't fortnightly, like rego or a quarterly power bill, turn them into a yearly total and divide by 26 before you split them. Our monthly bills article shows how.
One of you earns more. Splitting everything down the middle feels tidy, but the lower earner is left with very little each fortnight. Splitting by income feels fairer, but you're not sure how to do the maths, or whether it'll start an argument.
You're not the only ones. In a 2025 Finder survey of partnered Australians, 41% said they don't fully combine their finances, so plenty of couples are working out exactly this. Here are the three common methods, side by side, with the same numbers.
The three common ways to split
- Equal split (50/50): add up the shared bills and each pays half. Simple, and it can feel fair when your pays are close.
- Income share: each pays the same percentage of their own take-home pay. If you bring home 60% of the household's money, you cover 60% of the shared bills.
- Equal leftover: work out what's left of your combined pay after shared bills, halve it, and each pays whatever leaves them with that amount.
None of these is the right answer. They're just different ideas of fair. Equal split says “we each pay our way”. Income share says “we each give the same slice”. Equal leftover says “we each get the same life”.
Worked example
Sam and Alex, three ways
Example only. Sam and Alex rent in Brisbane. Sam takes home $2,400 a fortnight and Alex takes home $1,600, so $4,000 between them. Their shared bills, including rent and groceries, come to $2,500 a fortnight.
| Step | Sum | Result |
|---|---|---|
| Equal split: each pays half | $2,500 ÷ 2 | $1,250 each, so Sam keeps $1,150 and Alex keeps $350 |
| Income share: Sam's share | $2,400 ÷ $4,000 | 60%, so Alex's share is 40% |
| Income share: what each pays | $2,500 x 60% and $2,500 x 40% | Sam $1,500 and keeps $900, Alex $1,000 and keeps $600 |
| Equal leftover: what's left to share | ($4,000 minus $2,500) ÷ 2 | $750 each |
| Equal leftover: what each pays | $2,400 minus $750 and $1,600 minus $750 | Sam $1,650, Alex $850 |
The same $2,500 of bills leaves Alex with $350, $600 or $750 a fortnight depending on the method they choose.
Example only. In every method the two payments add up to $2,500.
How to work out the income share
- Write down each person's take-home pay for the same period, for example a fortnight.
- Add them together to get your combined take-home pay.
- Divide each person's pay by the combined total. That's their share.
- Multiply the shared bills by each share. That's what each person puts in.
For Sam and Alex, $2,400 ÷ $4,000 is 60% and $1,600 ÷ $4,000 is 40%. So Sam covers 60% of the $2,500 of shared bills and Alex covers 40%.
For equal leftover, take your combined pay, subtract the shared bills and halve what's left. Each of you keeps that amount, and pays in the rest of your own pay.
Use take-home pay, not salary
Use what actually lands in each account, not the salary on your contract. Tax, HECS-HELP repayments, salary sacrifice and child support can all make two similar salaries look very different on payday.
If either of you has income that goes up and down, like shifts, overtime or an ABN, use an average of the last few months and agree to check it again later.
What counts as a shared bill?
This is where most of the arguments really are. Agree the list first, then do the maths. Moneysmart suggests talking about how you'll split rent and bills, and using a simple budget to see your combined expenses.
- Usually shared: rent or mortgage, power, water, internet, groceries, home insurance, kids' costs, and holidays you take together.
- Often personal: your own phone, gym, hobbies, clothes, gifts for each other, and debts from before you got together.
- Talk about it: cars (especially if one person drives more), pets, and costs for family members.
When to redo the split
A split that was fair last year can quietly stop being fair. Redo the numbers when:
- either of you gets a pay rise, a new job or loses work
- one of you goes part-time, starts study or takes parental leave
- the shared bills change a lot, like a rent increase or a new baby
- it starts to feel unfair to either of you, which is reason enough
Worked example
Alex goes part-time
Example only. Alex drops to part-time and now takes home $1,200 a fortnight. Sam still takes home $2,400, so the combined pay is $3,600. Shared bills stay at $2,500.
| Step | Sum | Result |
|---|---|---|
| Equal split | $1,200 minus $1,250 | Alex would be $50 short every fortnight |
| Income share: Sam's share | $2,400 ÷ $3,600 | about 66.7%, so Alex's is about 33.3% |
| Income share: what each pays | $2,500 x 2/3 and $2,500 x 1/3 | Sam $1,666.67, Alex $833.33 |
| Equal leftover | ($3,600 minus $2,500) ÷ 2 | $550 each, so Sam pays $1,850 and Alex pays $650 |
After the change, 50/50 no longer works at all, so Sam and Alex move to income share or equal leftover.
Example only. Income share leaves Sam $733.33 and Alex $366.67.
Talking about it without a fight
Money talks can feel loaded, especially if you grew up with different rules about it. A few things help:
- Pick a calm time, not the night a big bill arrives.
- Run all three methods on your real numbers and look at them together.
- Talk about what each result leaves you to live on, not just who pays what.
- Agree a date to check it again, like every six months or after a pay change.
Key numbers
| What | Figure and source |
|---|---|
| Share of partnered Australians who don't fully combine finances | 41% (Finder survey of 559 respondents with a partner, January 2025) Finder |
| Moneysmart suggests discussing how you'll split rent and bills | Discuss shared costs Moneysmart |
| A simple budget helps couples see combined expenses | Use a budget Moneysmart |
| National Debt Helpline number and that it is free | 1800 007 007, free and confidential National Debt Helpline |
Free official help
- Moneysmart: Relationships and money
Talking about shared costs, joint accounts and shared debt. - Moneysmart: Marriage and money
Ways couples organise their money, and what to talk about first. - Moneysmart budget planner
Free planner to see your combined income and expenses. - National Debt Helpline
Free, confidential financial counselling on 1800 007 007 if money is getting on top of you.
Questions people ask
Is 50/50 unfair if one of us earns more?
Not automatically. If your pays are close, or the higher earner is happy with it, it can work well. It gets hard when the lower earner is left with very little, or can't cover their half at all.
Should we use gross salary or take-home pay?
Take-home pay. It's what you actually have to split, after tax, HECS-HELP repayments, salary sacrifice and anything else that comes out.
What if one of us has kids from a previous relationship?
Agree which of those costs are shared and which belong to that parent, then split the shared list with whichever method you pick. Write it down so it's clear.
How often should we redo the split?
Whenever either pay changes, or every six to twelve months. It only takes a few minutes once your bills list is set up.
Get the free pay check sheet
Type in one fortnight's pay and bills and see where it all goes. Works in Excel and Google Sheets.
Keep reading
- Joint or separate accounts? And how much fun money should we each get?
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- We get paid on different days. How do we run one budget?
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- How do we budget when one of us goes on parental leave?
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- How do I pay monthly bills when I'm paid fortnightly?
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- All couples and families guides
Sources
- Moneysmart: Relationships and money. https://moneysmart.gov.au/family-and-relationships/relationships-and-money, accessed 2026-10-16.
- Moneysmart: Marriage and money. https://moneysmart.gov.au/family-and-relationships/marriage-and-money, accessed 2026-10-16.
- Finder: Aussie couples don't fully combine their finances (2025). https://finder.com.au/news/aussie-couples-dont-fully-combine-their-finances-2025, accessed 2026-10-16.
- National Debt Helpline. https://ndh.org.au/, accessed 2026-10-16.