National Insurance calculator: what you pay in 2026/27
The National Insurance calculator works out Class 1 employee contributions for 2026/27: 8% on earnings above the primary threshold up to the upper earnings limit, then 2% above it. Unlike income tax, National Insurance is calculated per pay period, which is why a bonus month costs more NI than the same money spread across the year.
It is the one line on a payslip where the rate falls as earnings rise. Above the upper earnings limit an employee pays two percent, not eight.
Ask how the bonus is paid
Monthly beats a March lump sum for National Insurance. Income tax evens out by April either way, so the choice only moves NI, and it moves it in your favour.