Your employer works out employee NI from the earnings in each pay period and your contribution category. Your Income Tax code does not set the NI rate.
Checked . Based on official GOV.UK guidance. About our calculators and content.
Calculate employee National Insurance
Annual figures are averages
The calculator estimates category A NI for a year, then divides it into weeks or months. Your payslip uses pay-period thresholds and rounding, so irregular earnings can give a different result.
Checking an earlier year
NI rates changed during 2022/23 and 2023/24. The calculator averages those changes across steady annual earnings. It does not include contracted-out rebates or director-specific calculations.
Employer NI
Employer NI is usually an extra cost for the employer. With an umbrella company, the assignment budget can pay employer costs before employee gross pay is worked out. That is different from taking employer NI off your contractual gross salary.
Source: Read the original rules and guidance. Content checked 23 October 2026. General explanation, not personalised tax advice.