Bonus tax calculator — what you actually keep

No special bonus rate exists: a bonus is income stacked on top of your salary. This calculator differences the real band, NI and student-loan functions at salary versus salary-plus-bonus, so band crossings and the £100k taper price themselves. Your figures never leave your browser.

Why bonuses feel over-taxed

A bonus lands on top of your other income, so it's taxed entirely at your marginal rates — often a band above what your salary suggests, sometimes two. Crossing £100,000 is the sharp edge: the personal-allowance taper takes the effective rate to 60% (62% with NI) until £125,140. Payroll also sometimes over-withholds in the bonus month and corrects later — the annual arithmetic here is what you truly keep.

Bonus sacrifice is the counter-move: waived into your pension before payment, a bonus escapes income tax and NI entirely — the salary sacrifice calculator prices it exactly. The full Hundred Summers plan models bonuses (and their probability) across your whole projection.