How fair-share contributions are calculated

We add both partners' take-home incomes together, then find what percentage each partner contributes to that combined total. Each partner's fair share of your shared expenses uses that same percentage — so if Partner A earns 60% of your combined income, Partner A's fair share is 60% of your shared bills, and Partner B covers the remaining 40%.

Why not just split everything in half?

An even 50/50 split can quietly cost the lower-earning partner a much bigger share of their own paycheck. Splitting proportionally to income means each partner keeps roughly the same percentage of their own take-home pay free for everything else — savings, personal spending, whatever matters to them.

What this calculator doesn't do

• It doesn't categorize your spending — no needs/wants/savings breakdown, just the shared bills you enter here.
• It doesn't tell you how to structure your accounts — joint, separate, or a mix of both work with this math.
• This is a starting point for a conversation, not financial advice — see Chapter 2 of Newlywed Money Management for the full discussion of proportionate contribution.