Split shared costs as a couple, 50/50 or by income

Couples rarely argue about the arithmetic. They argue about what feels fair, especially when one partner earns a lot more than the other. The couples expense calculator above opens in Split by income mode: enter your shared monthly costs and both incomes, and it shows what each of you pays so that you both pay the same percentage of what you earn.

If you would rather split 50/50, switch to Split evenly with two people. The worked example below puts the two side by side, plus a third option, so you can see the money each of you has left, not just the bill.

How to use the couples expense calculator

1. Keep Split by income selected.
2. Enter your total shared costs for the month as the Bill total, for example rent plus groceries plus utilities.
3. Type each Name and Monthly income. Use take-home pay for both of you.
4. Read each share and its percentage of the bill.
5. Tap Share result to send the numbers to your partner.

For a 50/50 split, tap Split evenly, set Number of people to 2 and choose No tip.

Worked example: $2,750 a month, two incomes

Sam takes home $6,200 a month and Alex takes home $3,800, so together they earn $10,000. Their shared costs are:

Shared cost	Monthly
Rent	$1,800
Groceries	$650
Electricity, water and gas	$240
Internet	$60
Total	$2,750

The shared costs are 27.5% of their combined income ($2,750 ÷ $10,000). Here is what each method means for them.

Method	Sam pays	Alex pays	Sam has left	Alex has left
50/50	$1,375	$1,375	$4,825	$2,425
By income (62% / 38%)	$1,705	$1,045	$4,495	$2,755
Equal money left over	$2,575	$175	$3,625	$3,625

By income is what the calculator shows: Sam pays $2,750 × 6,200 ÷ 10,000 = $1,705 and Alex pays $2,750 × 3,800 ÷ 10,000 = $1,045. Each of them pays 27.5% of their own income.

Equal money left over treats the two incomes as one pot: $10,000 − $2,750 = $7,250, and half of that is $3,625 each. Sam pays $6,200 − $3,625 = $2,575 and Alex pays $3,800 − $3,625 = $175. It is close to fully joint finances.

How the rounding works. When a share does not come out in whole cents, the calculator gives the leftover cent to the share that was closest to rounding up. A $1,000 bill with incomes of $2,000 and $1,000 becomes $666.67 and $333.33, which adds up to exactly $1,000.00.

Which split fits your relationship

Your situation	A split that often feels fair
Similar incomes	50/50
One earns clearly more, finances kept separate	By income
Married or long term, money treated as shared	Equal money left over, or a joint account
One partner does more unpaid work, such as childcare	By income, and count that work when you agree the split
Incomes change often, freelance or seasonal	By income, recalculated each month

There is no right answer that suits every couple. The test is whether both of you would still call the split fair if your incomes were swapped. Talk about it once, write down what you agreed, and look at it again when a job, a move or a baby changes the numbers.

When a calculator is not enough

The calculator answers what each of you should pay. In real life one of you pays the rent, the other does the big shop, and a dozen small things go on whichever card is closest. Half Tab keeps a running balance for the two of you: add each expense as it happens, split it equally, by exact amounts, by shares or by percentage (62% and 38%, for example), and the app shows who owes whom. Its personal tab also records money one of you lends the other outside your shared costs. It works offline on iPhone and iPad, and no account is needed to start.

More calculators and guides

• The rent split calculator for rent by room size or income.
• The utility bill splitter for monthly bills.
• The main split bill calculator.
• Our guides on how to split bills as a couple and how to split bills based on income.