Multi-Income Tax Calculator
Calculate your combined tax position across multiple income sources
Your Income Sources
Add Income Source
Tax Details and Deductions
Scotland has different income tax bands
Monthly deductions taken from salary before tax, excluding pension (e.g. cycle-to-work, electric car)
Monthly donation amount — we gross up for Gift Aid automatically
How Tax Works Across Multiple Income Sources
When you have more than one source of income — whether that's a salary alongside self-employment, rental property, or a side job — HMRC aggregates everything and applies a single set of tax bands. Your Personal Allowance of £12,570 is applied once across all your income, not separately to each source.
National Insurance is treated differently by income type. You pay Class 1 NI on employment earnings, Class 4 (and small Class 2) NI on self-employment profit, and no NI on rental income or dividends. This means the same pound of income can carry different total tax costs depending on its source.
If your self-employment profit exceeds £1,000 or your rental income (before expenses) exceeds £2,500, you must register for Self Assessment. Combined incomes over £100,000 trigger the personal allowance taper — creating an effective 60% marginal rate — and any income over £60,000 risks the High Income Child Benefit Charge if you have children.
Pension contributions reduce your adjusted net income across all sources, which can lower both your income tax band and restore Child Benefit that would otherwise be lost. Our calculator models all of these interactions in one view.