Work out joint account contribution split instantly with clear inputs, formula shown and shareable results.
An equal split is simple but takes a larger share of the lower income. A proportional split equalises the burden as a percentage of income, which is why it is the fairer default when incomes differ materially.
Proportional split
Each contribution = shared expenses × that partner's income / combined income
Figures are estimates for planning only. Prices, returns, inflation and personal circumstances all change. This is not financial or tax advice — speak to a qualified adviser before making decisions.
Proportional splitting, because it equalises the strain rather than the amount.
Most couples keep a personal allowance outside the pool, which reduces friction considerably.