Household account merge simulator

When two incomes start sharing costs, the question is not whether to pool money but how to divide the contribution. This tool adds shared spending and shared saving into one monthly figure, then shows two ways to fund it — an even 50/50 split and a split proportional to income — with what each partner keeps under each. The numbers do not decide what is fair; they show the trade-off so you can talk about it.

Result

Shared spending plus shared saving means the joint account needs 12,000 a month. Split in proportion to income, A pays in 7,500 (keeps 4,500), and B pays in 4,500 (keeps 2,500). Switch to an even 50/50 and each pays 6,000 — noticeably tighter for the lower earner.

Joint account needs / month: 12,000
A pays / keeps (proportional): <strong>7,500</strong> / 4,500
B pays / keeps (proportional): <strong>4,500</strong> / 2,500
Each pays (50/50): 6,000

The joint account need, split into A’s and B’s shares in proportion to income.

Arithmetic on your inputs, not a recommendation for how to divide money.

Assumptions & limits

A 50/50 split leaves the lower earner much tighter; the proportional split can push a low income below zero. The numbers do not judge what counts as fair.