Should couples split bills proportionally by income?

Proportional splitting – each partner pays a share of joint expenses equal to their share of combined income – is often fairer than 50/50 when incomes differ a lot. If one partner earns $90,000 and the other $60,000, the split is 60/40, so the same dollar of 'fun money' leftover feels equal rather than crushing the lower earner. To set it up, add both incomes, find each person's percentage, and apply that to the total of shared bills. The alternative, treating all income as one pot, is even simpler and works well for fully committed couples. There's no legally right answer; pick what feels equitable to both of you and revisit it when incomes change. Recalculate the percentages after any raise, job change, or new shared expense.