Proportional bill split calculator
Enter both incomes and shared monthly bills to calculate an income-based split, compare it with 50/50 and check whether each partner keeps enough personal money.
Content reviewed and refreshed on 15 Sep 2026.
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Takes ~ 1 minuteYour result
Fill in the fields above and click Calculate — your personalised plan appears here in a moment.
How proportional bill splitting works
A proportional split divides shared bills by each partner’s share of total household income. If Partner A earns 60% of the combined income, Partner A pays 60% of the shared bills and Partner B pays 40%.
When it is useful
This method is most useful when incomes differ enough that a 50/50 split would leave one partner with far less personal money. It does not decide which expenses belong in the shared budget; agree that list first, then use the calculator for the math.
What to review together
Recalculate after a raise, parental leave, unemployment, a new rent contract, childcare or a large recurring bill. The goal is not to make every purchase identical, but to make the household contribution transparent.