Split bills fairly by income. Enter both take-home incomes and your shared monthly costs to see a proportional split next to a straight 50/50, and how much each of you keeps after shared bills.
A proportional split gives each partner a share of the shared costs equal to their share of combined income. If one partner earns 60% of the household take-home pay, they cover 60% of rent, utilities, and other shared bills.
The formula is simple: your share = shared costs × (your income ÷ combined income). The calculator runs that for both partners, then shows a 50/50 split beside it so you can see how far apart the two approaches are for your numbers.
The leftover figures are what each partner keeps after shared bills. Comparing leftovers is often the fastest way to tell whether a split feels fair in practice.
There is no single right answer. A common approach is proportional: each partner pays the same percentage of their income toward shared costs, so the higher earner pays more in dollars but both feel the same squeeze. A 50/50 split is simpler but can leave the lower earner with much less breathing room.
Add both take-home incomes together, divide each income by that total to get each partner’s percentage, then multiply the rent by each percentage. For example, on
Take-home pay usually gives a more honest picture, because it is the money actually available for bills after taxes and retirement contributions.
Anything you both benefit from: rent or mortgage, utilities, groceries, insurance you share, internet, and joint subscriptions. Personal spending usually stays out of the pot.
Related reading: Two incomes, one picture, Money talks that stay calm. More free calculators at theflan.app/tools.