Works out Class 1 National Insurance for one pay period in 2026/27: the employer's contribution, the employee's deduction, and the total cost of the employee to the employer.
This calculator runs in your browser: nothing you enter is sent anywhere. It is a guide, not advice, and does not replace your payroll software's calculation.
How It Is Worked Out
- National Insurance is worked out on each pay period separately, against that period's thresholds. It is not cumulative.
- Employer NI is 15% of pay above the Secondary Threshold: £96 a week, £417 a month. For categories H, M, V and Z there is none until pay passes the Upper Secondary Threshold, £967 a week or £4,189 a month.
- Employee NI is 8% of pay between the Primary Threshold (£242 a week, £1,048 a month) and the Upper Earnings Limit (£967 a week, £4,189 a month), and 2% above it. Category B pays 1.85% in place of 8%, J and Z pay 2% throughout, and C pays none.
- Each amount is rounded to the nearest penny, with an exact half penny rounded down. Checked against HMRC's published 2026/27 test data: employer NI agrees to the penny, and employee NI can differ by a penny where pay is within a few pence of a threshold.
The yearly figures assume the same pay in every period. They take no account of the Employment Allowance, which can remove up to £10,500 of employer NI a year across the whole payroll: see Employment Allowance 2026/27. Company directors are assessed differently: use the directors' NI calculator.
All the thresholds are in NI rates and thresholds 2026/27.