About this NI calculator
UK National Insurance calculator for employee, employer and self-employed NI
The Free Calculators UK National Insurance Calculator helps users estimate National Insurance contributions for the 2026/27 tax year. It supports employee Class 1 NI, employer Class 1 NI and self-employed Class 4 NI, making it useful for employees, employers, contractors, freelancers and payroll users.
Employee National Insurance is normally deducted through PAYE. Employer National Insurance is paid by the employer and should not be deducted from the employee’s wages. Self-employed people may pay Class 4 National Insurance on profits above the relevant profit limits.
Employee National Insurance
For standard Category A employees in 2026/27, employee NI is calculated at 8% on earnings between the Primary Threshold and Upper Earnings Limit, and 2% on earnings above the Upper Earnings Limit. Reduced-rate and deferred-rate category options can produce different results.
Class 1 employee NI is usually calculated by pay period rather than cumulatively like income tax. That means weekly and monthly payroll results can differ from a simple annual average if earnings fluctuate during the year.
Employer National Insurance
Employer Class 1 National Insurance is usually calculated on earnings above the Secondary Threshold. For 2026/27, the standard employer rate is 15%. Some categories, such as under-21 employees, certain apprentices, veterans, Freeport employees and Investment Zone employees, may have a zero-rate band up to a specified upper secondary threshold.
This calculator includes a standard employer mode and special category options. It does not apply Employment Allowance automatically because eligibility depends on the employer’s circumstances.
Self-employed National Insurance
Self-employed people may pay Class 4 National Insurance on profits above the Lower Profits Limit. For 2026/27, the calculator applies 6% between the Lower Profits Limit and Upper Profits Limit, and 2% on profits above the Upper Profits Limit.
The tool also includes an optional Class 2 weekly contribution estimate. Class 2 can be relevant for voluntary contributions or special cases, but the calculator keeps it optional so users can decide whether to include it.
Important limitation
This calculator is for general estimation only. It does not replace HMRC payroll software, PAYE tools, director annual earnings methods, special occupational rules, exact payroll rounding, multiple employments, deferment certificates, Employment Allowance or every category-letter situation.
For official payroll, employer reporting, director calculations, Class 1A, Class 1B, benefits, termination awards or complex self-employment cases, users should check HMRC guidance or speak with a qualified payroll or tax adviser.
Why Free Calculators is useful for UK payroll planning
Free Calculators is designed to provide practical online calculators for tax, payroll, salary and finance planning. A UK National Insurance calculator is useful because NI affects take-home pay, employer cost and self-employed tax planning.
This page includes SEO metadata, structured data, FAQ schema, responsive calculator design and detailed explanatory content. The same structure can be reused for UK income tax calculator, UK salary calculator, PAYE calculator, employer cost calculator and self-employed tax calculator.