Free tool
Split an expense by income
Enter the shared expense and each person's income: the tool works out a proportional contribution, down to the cent.
The expense to share
Each person's income
Net income for the relevant period (monthly for a monthly bill). Incomes are only used as weights and never leave your browser.
Total
€0
What everyone owes
Enter the amounts to see the split.
Each contribution is proportional to the income entered: twice the income means twice the contribution.
Everything is computed in your browser: nothing is stored or sent.
Whole-cent arithmetic with a largest-remainder distribution of the leftovers: the shares are checked against the total by automated tests.
For tracking several expenses over time, with your friends.
How proportional splitting works
Splitting a bill 50/50 between two people whose incomes differ threefold creates real imbalance: the same amount is a very different effort depending on the budget behind it. A proportional split fixes that by relating each contribution to the person's income.
Concretely, with incomes of 2,000 and 1,000, the higher earner takes two thirds of the expense and the other one third. The effort rate — the share of income spent — becomes identical for both.
Which income to use
The usual choice is net monthly income after tax, including bonuses if they are regular. For irregular income, use a twelve-month average rather than last month, otherwise the split changes every month.
Some couples prefer disposable income: net income minus strictly personal commitments such as a pre-existing loan. It can be fairer, but it is harder to keep up to date, so pick a simple rule and stick with it.
A method, not an obligation
Income-based splitting fits structural costs well: rent, groceries, energy, shared holidays. For leisure spending chosen by one person, an equal split or individual payment can be preferable.
You are not forced to apply it fully either. Some households use an intermediate key, halfway between 50/50 and strict proportionality. What matters is that the rule is explicit and accepted by everyone.
Frequently asked questions
Is my income sent anywhere?
No. The calculation is entirely local to your browser: no income, amount or name is sent to a server, stored, or placed in the page address.
What if someone has no income?
Their contribution comes out at zero. That follows from the proportional rule, but it assumes everyone agreed that the others would cover the expense in full.
Can I use it for rent?
Yes, that is a very common use for couples. If you would rather split by bedroom size, use the rent split calculator instead.
Editorial review — Written and reviewed by the Pivunio team. The methods described here are the ones the app itself uses, and they are covered by automated tests.