Most couples who live together end up using both methods: they split big fixed costs like rent and utilities by income, and split everyday costs like groceries and dinners out 50/50. Splitting by income keeps the largest bills fair when one of you earns more. Splitting the small stuff evenly keeps it simple. If your incomes are close, 50/50 for everything is usually fine.
The rest of this post shows the math for one month of shared costs done three ways, how to decide which costs go where, and how to settle up with one transfer a month.
The three common setups
Split everything 50/50
Every shared cost is split down the middle. It is easy to explain and easy to track. It works best when you earn about the same.
Split everything by income
Each of you pays the same percentage of your take-home pay toward every shared cost. If one of you brings home 65% of the household's pay, that person covers 65% of everything. It is the most even in terms of what each paycheck carries, and the most math.
Mix the two
Big, predictable costs are split by income. Smaller, day-to-day costs are split 50/50. Many couples land here after trying one of the other two.
If rent is the only cost you want to split by income, we walk through that math on its own in how to split rent when you earn different amounts, and the rent split calculator does it for your own numbers.
Worked example: one month, three ways
Say one of you takes home $6,500 a month and the other takes home $3,500. Together that is $10,000, so the split by income is 65% and 35%.
Your shared costs for the month:
- Rent: $2,200
- Utilities and internet: $200
- Groceries: $700
- Dinners out and takeout: $300
- Streaming: $40
That adds up to $3,440.
50/50 for everything
Each of you pays $1,720. For the person taking home $6,500, that is about 26% of their pay. For the person taking home $3,500, it is about 49%, close to half of everything they bring home.
Everything by income
The higher earner pays 65% of $3,440, which is $2,236. The other pays 35%, which is $1,204. Check it: $2,236 + $1,204 = $3,440. Shared costs now take about 34% of each paycheck.
The mix
Rent and utilities are the fixed costs: $2,400. Split 65/35, that is $1,560 and $840.
Groceries, dinners and streaming are the everyday costs: $1,040. Split 50/50, that is $520 each.
Add them up:
- Higher earner: $1,560 + $520 = $2,080, about 32% of their pay
- Lower earner: $840 + $520 = $1,360, about 39% of their pay
Check it: $2,080 + $1,360 = $3,440.
The mix sits between the other two. The lower earner pays $360 less than with 50/50, and the everyday costs stay easy to split on the spot.
Which costs go in which bucket
A simple test: split a cost by income if it is large, regular and something you both need. Split it 50/50 if it is small, frequent, or something you both choose in the moment.
Usually split by income:
- Rent or mortgage
- Utilities, internet and renter's insurance
- Shared car payments and car insurance, if you share a car
- Childcare, if you have kids
Usually split 50/50:
- Groceries and household supplies
- Dinners out, takeout and coffee together
- Shared subscriptions
- Small things for the home
The line does not have to be perfect. What matters is that you both know where it is before the bills arrive, so nobody has to argue about a $30 takeout order.
The gray areas
Some costs do not fit either bucket cleanly. Here is how couples often handle them.
Trips: Big trips are often split by income, since a $3,000 vacation is a bigger bite for the lower earner. Weekend trips often go 50/50 like dinners.
A cost only one of you really wants: If one of you wants the bigger apartment or the premium gym, a common answer is that the person who wants the upgrade pays the difference.
Pets: If the pet is shared, treat food and vet bills like groceries. If it came with one of you, that person often keeps paying for it.
Gifts for family: Many couples keep these personal. Each person pays for gifts to their own family.
Treat these as starting points you can agree on in a few minutes.
Settling up once a month
You do not need to split every receipt as it happens. Most couples have one person pay some bills and the other pay the rest, then even out once a month.
Using the example above, say the higher earner pays rent, utilities and streaming: $2,440. The lower earner pays groceries and dinners out: $1,000.
- The higher earner's share is $2,080. They paid $2,440, so they are owed $360.
- The lower earner's share is $1,360. They paid $1,000, so they owe $360.
One $360 transfer at the end of the month and you are even. The two numbers always match: if they don't, a cost was missed or counted twice.
A shared list helps here. Many couples use Splitwise or a simple shared note, and add each cost the day it is paid along with which bucket it belongs to.
Counting your share in your own budget
If you each keep your own budget, count only your share of shared costs as your spending.
Take the lower earner in the example. Their card shows $1,000 of groceries and dinners. Their real share of the month's shared costs is $1,360: $840 of rent and utilities plus $520 of everyday costs. That $1,360 is what the shared life cost them this month, rather than the $1,000 on their card or the $3,440 the two of you spent together.
The same goes for the transfer. The $360 the higher earner receives at the end of the month is not income. It is their partner's share of bills they already paid, so it lowers what those bills cost them.
When to revisit the split
Write down the percentages and which costs go in which bucket. Look at them again when:
- Either of you changes jobs or gets a raise
- The lease renews or rent changes
- You move in together for real after a trial period, or start combining more of your money
A quick check once a year is enough for most couples. The goal is a split you both picked on purpose.
If you share accounts with a partner, Monio's household view adds up the accounts each of you chooses to share and leaves out money moved between you, so a monthly settle-up transfer isn't counted as spending or income.
Questions
Should couples split expenses 50/50 or by income?
Most couples who live together use both: they split big fixed costs like rent and utilities by income, and everyday costs like groceries and dinners out 50/50. If your incomes are close, 50/50 for everything is usually fine.
How do you split expenses by income as a couple?
Each of you pays the same percentage of your take-home pay toward every shared cost. If one of you takes home $6,500 a month and the other $3,500, the split is 65% and 35%.
Which expenses should couples split by income?
Split a cost by income if it is large, regular and something you both need, like rent, utilities, internet, renter's insurance, a shared car or childcare. Small, frequent costs you choose in the moment, like groceries and dinners out, usually go 50/50.
How do couples settle up shared expenses?
Most couples have one person pay some bills and the other pay the rest, then even out with one transfer a month. What one person is owed always matches what the other owes; if it doesn't, a cost was missed or counted twice.