Finance & Money
Rates & guidance reviewed
National Insurance (NI) is one of the largest deductions on a UK payslip — and for employers, Class 1 secondary contributions are a major payroll cost. This free UK National Insurance calculator estimates employee Class 1, employer Class 1 and self-employed Class 4 NI from annual earnings or profits.
Switch between employee, employer and self-employed modes to see annual, monthly and weekly amounts, plus a simple band breakdown. National Insurance rules are UK-wide (unlike Income Tax in Scotland). Everything runs privately in your browser.
Figures use commonly published thresholds and rates for guidance only. Directors, multiple jobs, benefits in kind, Employment Allowance and special categories can change the real bill — confirm with HMRC or a payroll professional.
Prefer the written walkthrough? Start with How UK take-home pay is calculated (2026/27), How UK student loan repayments work (2026/27), How UK National Insurance is calculated (2026/27) or How UK pension salary sacrifice compares to relief at source. Guides match the figures on this page.
Illustrative UK NI structure · verify current tax year on GOV.UK
Salary before tax and employee NI
0% NI
8% → £1,794.40 NI
For Income Tax plus employee NI and net pay together, use the take-home pay calculator. To model pension salary sacrifice and NI on reduced pay, use the salary sacrifice calculator. Student loan deductions are separate — see the student loan calculator.
Static sample calculations you can read without using the form. Figures match this tool's maths — always re-run with your own numbers for a personal estimate.
Class 1 primary NI only — typical full-time salary below the UEL.
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8% on earnings between PT £12,570 and £30,000.
Still entirely in the main employee NI band in this model.
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Part of pay above the Upper Earnings Limit at the 2% rate.
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8% from PT to UEL £50,270, then 2% on the remainder.
Class 1 secondary cost to the business (not deducted from net pay).
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Illustrative 15% above a £5,000 secondary threshold.
Class 4 on trading profits above the Lower Profits Limit.
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Most employees pay Class 1 primary NI on earnings above the Primary Threshold. Between the Primary Threshold and the Upper Earnings Limit a main percentage rate applies; above the Upper Earnings Limit a lower additional rate applies. Earnings at or below the Primary Threshold usually attract no employee NI on that slice.
Illustrative structure used here: Primary Threshold £12,570 a year, Upper Earnings Limit £50,270, main employee rate 8%, additional rate 2%. Thresholds are often expressed weekly or monthly on official tables — we annualise for a simple salary model.
Worked case: on £30,000 gross, employee NI is about £1,394 a year in this tool (8% on £17,430 above the Primary Threshold). Pair with the take-home pay calculator to see Income Tax and NI together.
Employers pay Class 1 secondary NI on most employees’ earnings above the Secondary Threshold. From April 2025, commonly published rules use a higher employer percentage and a lower secondary threshold than in earlier years — this tool models an illustrative 15% rate above a £5,000 annual secondary threshold.
Employment Allowance, freeports, veterans’ relief and other schemes can reduce employer NI for eligible businesses. Those reliefs are not modelled here. Employer NI is a cost to the business, not a deduction from the employee’s net pay.
Self-employed people with profits above the Class 4 Lower Profits Limit typically pay Class 4 NI at a main rate up to the Upper Profits Limit and a lower rate above that. Class 2 NI has changed in recent years (including periods where it is treated as £0 for many people while National Insurance credits can still apply under specific rules).
This calculator focuses on Class 4 profit-based estimates. Trading allowance, partnership shares and partial-year trading need careful Self Assessment treatment — use HMRC guidance or an accountant for filings.
Always confirm rates, bands and eligibility on official pages. Our tools are simplified estimators for guidance only.