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Reference · UK 2026/27

What is National Insurance?

National Insurance is a tax on UK earnings used to fund the State Pension, contribution-based benefits (Job Seeker's Allowance, Maternity Allowance), and a slice of the NHS. The system has five "classes" depending on your employment status.

3-minute read

National Insurance (NI) is a UK payroll tax on earned income, separate from Income Tax. In 2026/27, employees pay 8% on earnings between £12,570 and £50,270, then 2% above £50,270. The self-employed pay Class 4 at the same rates. Your NI record determines your future State Pension entitlement.

The five NI classes (2026/27)

ClassWho pays2026/27 rate
Class 1 (employees)Employed earners8% (£12,570-£50,270), 2% above
Class 1A (employer)Employer on BIKs15% of cash equivalent
Class 1BEmployer on PSA items15%
Class 2Self-employed (abolished from Apr 2024 for most)Voluntary £3.60/week if profits under £6,725
Class 3Voluntary top-ups£18.40/week (£956.80 a year)
Class 3AHistoric (closed)n/a
Class 4Self-employed6% (£12,570-£50,270), 2% above

You stop paying NI when you reach State Pension age, regardless of whether you keep working. The threshold is £12,570 for both Class 1 and Class 4 — the same as the Income Tax Personal Allowance, by design.

How NI affects your State Pension

Your NI record determines two things:

Worth checkingYour NI record at gov.uk/check-state-pension shows every year you've contributed or received credits. Gaps before age 66 can sometimes be filled with voluntary Class 3 contributions (~£956.80 per missing year, can boost State Pension by ~£328 a year for life — typically breaks even within 3-4 years of claiming).

The should I top up state pension page works through the decision framework. The State Pension forecast calculator projects your eventual pension based on your record.

NI vs Income Tax — six key differences

AspectIncome TaxNI
Threshold£12,570£12,570 (PT)
Top rate kicks in at£125,140 (45%)£50,270 (drops to 2%)
Applies to pensions in payment?YesNo
Applies after State Pension age?YesNo
Reduces with pension contributions?Yes (relief at marginal rate)Only with salary sacrifice
Builds entitlement?NoYes (State Pension)

The "drops to 2%" feature at £50,270 is unusual. It means high earners pay a smaller NI marginal rate than basic-rate earners (2% vs 8%) — though their income tax marginal rate is higher. The combined effect for higher earners: 42% combined marginal on the £50,270-£100,000 slice, vs 28% combined on the £12,570-£50,270 slice.

Common NI mistakes

Mistake 1Not checking your NI record before age 60. Gaps can be filled cheaply, but only within 6 years generally (sometimes extended). Leaving it to age 65 may be too late.
Mistake 2Self-employed thinking Class 4 NI builds State Pension contributions. It does — same as Class 1. The old confusion about Class 2 was that you needed it separately; Class 2 was largely abolished from April 2024.
Mistake 3Forgetting NI stops at State Pension age. If you work past 66 (or your pension age), you stop paying employee NI immediately. Your employer's Class 1A NI on BIKs still continues.

Check your full UK take-home

The tax calculator handles all NI classes, Scotland, student loans and salary sacrifice. See your real net pay for any scenario.

Open the UK tax calculator →

Sources and methodology

NI rates, thresholds and class definitions from gov.uk/national-insurance-rates-letters. State Pension qualifying years from gov.uk/new-state-pension. Voluntary Class 3 rules from gov.uk/voluntary-national-insurance-contributions.

UK Tax Drag is not authorised by the Financial Conduct Authority and does not provide regulated financial advice — see the content disclaimer for the full position. The methodology page documents how every calculator is built and reviewed.

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