Bonus & Overtime Net Pay Calculator
See the actual take-home value of a one-off bonus or overtime payment, after Income Tax and National Insurance.
Baseline net pay (this month)
£2,393.30
Net pay with extra (this month)
£3,731.45
HMRC-compliant payroll software taxes a one-off bonus or overtime payment by treating it as if you earned that amount every month of the year, which is why a large bonus can be taxed at a higher marginal rate than your normal salary in the month it's paid. Any difference is usually balanced out over the rest of the tax year through your normal cumulative tax code. This estimate assumes the standard 1257L tax code and does not include pension contributions or student loan repayments.
Why a bonus is sometimes taxed more heavily
A bonus or overtime payment is added to your normal salary for the pay period in which it's paid. Because PAYE calculates tax as if that higher pay period repeated every month of the year, a large bonus can push your marginal earnings cleanly into the 40% or 45% tax bracket for that one payslip, even if your underlying annual salary wouldn't normally reach those bands.
This doesn't mean you permanently lose that money — if the bonus genuinely pushes your total annual income into a higher bracket, that's correct tax; but if it was a one-off spike, HMRC's cumulative tax system typically corrects the balance over the remaining months of the tax year, or via a tax return or rebate.