Written by the TaxTune Editorial Team · Reviewed by our qualified accountants · Updated for 2026
The quick answer National Insurance is a tax on earnings that builds your entitlement to the state pension and some benefits. Employees pay Class 1 through PAYE, employers pay a separate Class 1 contribution, and the self employed pay Class 4. Voluntary Class 3 can fill gaps in your record.

The main classes

  1. Class 1 (employees). Deducted from pay through PAYE above the earnings threshold.
  2. Class 1 (employers). Paid by the employer at 15% on earnings above the secondary threshold.
  3. Class 2 and Class 4 (self employed). Class 4 at 6% then 2% on profits, with Class 2 largely no longer payable but still building entitlement.
  4. Class 3 (voluntary). Paid to fill gaps and protect your state pension where you have missing years.

Why it matters

National Insurance is not just a deduction. Building enough qualifying years is what secures your full state pension, and certain benefits depend on your record. Checking your record and topping up gaps where worthwhile can be one of the best value financial decisions you make.

Gaps in your record?

Missing National Insurance years can quietly reduce your state pension. TaxTune checks your position and advises whether topping up is worthwhile for you.

See how we can helpAsk about your record

Let us check your National Insurance

We work out what you owe, check your record for gaps, and advise on protecting your state pension. Fixed fee.

Get a fixed fee quoteTalk to a real accountant

Keep reading

Frequently asked questions

What is National Insurance for?

It is a tax on earnings that funds the state pension and certain benefits, and builds your personal entitlement to them through qualifying years on your record.

What National Insurance do employees pay?

Employees pay Class 1 National Insurance through PAYE on earnings above the threshold. Employers pay a separate Class 1 contribution at 15% above the secondary threshold.

What do the self employed pay?

Class 4 National Insurance at 6% on profits between £12,570 and £50,270, then 2% above. Class 2 is largely no longer payable but still builds benefit entitlement.

Can I fill gaps in my record?

Yes. Voluntary Class 3 contributions can fill gaps and protect your state pension. Whether it is worthwhile depends on your years and circumstances.

How many years do I need for the state pension?

You generally need around 35 qualifying years for the full new state pension, and at least 10 to receive any. Checking your record early gives time to fill gaps.