Couple budget calculator: who pays what, and how much?

How this split expenses calculator for couples works

Enter each partner's net monthly income and the total of the expenses you share: rent or mortgage, energy, groceries, insurance, transport, childcare. The calculator then shows how much each of you should pay with three methods — 50/50, pro rata to income, or equal money left — and what remains for each person at the end of the month.

How to split bills based on income: 3 methods

50/50: each partner pays half. Simple and transparent, it works well when incomes are close. When one earns much more, the lower earner can end up with very little left.

Pro rata: each partner contributes the same percentage of their income. It is the method most couples consider fair when incomes differ, because the effort is proportional.

Equal money left: the split is adjusted so that both partners keep exactly the same amount after the shared bills. It is the most redistributive option, often chosen by married couples or families with children.

Worked example

Alex earns 2,800 and Sam 1,900 per month; shared expenses are 1,800. With 50/50, each pays 900: Alex keeps 1,900, Sam only 1,000. Pro rata (59.6% / 40.4%), Alex pays 1,072 and Sam 728: Alex keeps 1,728, Sam 1,172. With equal money left, Alex pays 1,350 and Sam 450, and both keep 1,450.

Joint account, separate accounts or both?

Most couples use a hybrid setup: each partner transfers their share into a joint account that pays the shared bills, and keeps a personal account for everything else. The calculator gives you the exact monthly transfer for each person. Review it whenever an income changes — a raise, parental leave or a new job.