National Insurance: what it is, what it pays for, and why checking your record matters

National Insurance and income tax both appear on your payslip, and both go to the government. But they are separate systems with different rules, and they serve different purposes.

Income tax is collected by HMRC and funds general government expenditure. National Insurance is also collected by HMRC but is specifically tied to your entitlement to the State Pension and certain contributory benefits.

Each year in which you pay enough NI (or receive NI credits) is called a qualifying year. These qualifying years build your State Pension entitlement over your working life. Every qualifying year you are missing is a year you did not earn toward your pension.

That is why it is worth checking your record. Some people have gaps they do not know about: periods of low earnings, career breaks, time spent caring for children or family members, or years spent abroad.

There are different classes of National Insurance depending on how you earn your income. Verify all current rates and thresholds at GOV.UK National Insurance rates before acting on any figures, as rates change each April and sometimes mid-year.

Class 1 is paid by employees and their employers. As an employee, you pay Class 1 NI on earnings above the Primary Threshold. Your employer also pays employer's NI on your earnings above the Secondary Threshold — this is separate from your contribution and does not affect your take-home pay directly, though it affects the total cost of employing you. The employer NI rate changed in the October 2024 Budget. Verify the current rate at GOV.UK.

Class 2 applies to self-employed people. This class has been subject to significant changes in recent years — it was proposed for abolition and the position has changed. Verify the current status and any obligations at GOV.UK self-employed NI at build time before relying on any figures here.

Class 3 is voluntary contributions. You pay these to fill gaps in your NI record if you were not earning above the threshold or not getting NI credits. The weekly rate for Class 3 voluntary contributions is set each year — verify the current rate at GOV.UK voluntary NI. As of April 2025 the rate was £17.45 per week, but this changes annually.

Class 4 is paid by self-employed people on profits above the lower profits limit. It is collected through Self Assessment alongside income tax. Verify current rates and thresholds at GOV.UK.

Your NI contributions fund:

• The State Pension — this is the main purpose of NI. Your qualifying years determine how much State Pension you receive at retirement age.
• Contribution-based Jobseeker's Allowance — you need a certain number of NI contributions in recent tax years to be entitled to this form of JSA.
• Contribution-based Employment and Support Allowance — similar NI requirements for those unable to work due to illness or disability.
• Maternity Allowance — requires a minimum number of qualifying weeks as an employee or self-employed person.
• Bereavement Support Payment — paid to widows and widowers who meet NI contribution tests.

NI does not fund the NHS directly, despite what many people believe. NHS funding comes from general taxation. The link between NI and NHS spending that existed historically was removed when the systems were restructured.

These are two different things that often get confused.

Your NI number is a reference number that identifies you in HMRC's system throughout your life. It looks like two letters, six digits, then one letter (e.g. QQ 12 34 56 A). It is assigned when you are around 16 years old. It does not change.

Your NI contributions are the actual payments made to HMRC that build your qualifying years. Having an NI number does not mean you are contributing — you only build qualifying years when you earn above a certain threshold, are self-employed with sufficient profits, or receive NI credits.

You do not always need to be earning to build qualifying years. NI credits are awarded in certain circumstances, and they count the same as paid contributions for State Pension purposes.

You receive NI credits if you:

• Are claiming Child Benefit for a child under 12 (an important one for parents who take career breaks)
• Are receiving certain benefits including Universal Credit or Jobseeker's Allowance
• Are a carer providing at least 20 hours a week of unpaid care (Carer's Credit)
• Are taking a break from work to care for a child through Specified Adult Childcare credits

If you left employment to care for children and did not claim Child Benefit, you may have gaps in your record. You can sometimes apply retrospectively for Specified Adult Childcare credits. Check your record and GOV.UK NI credits to see what applies.

A gap in your NI record means a tax year in which you did not earn enough, were not contributing, and did not receive NI credits. Each gap is a year not counting toward your State Pension.

You can check your record through the Personal Tax Account or State Pension forecast on GOV.UK. The forecast shows you how many qualifying years you have, how many you need for the full pension, and whether you have any gaps.

For recent gaps, you may be eligible to pay voluntary Class 3 contributions to fill them. The cost and the benefit depend on how many years you are missing and how close you are to State Pension age.

One important deadline: the rules on how far back you can pay voluntary contributions have changed several times. There has been an extended window to pay for gaps going back to 2006, but deadlines have applied and may still apply. Check GOV.UK voluntary NI for the current position — if a deadline is imminent or has recently passed, this is worth knowing before assuming you can fill gaps at any time.

The full new State Pension requires 35 qualifying years. You need at least 10 qualifying years to receive any State Pension at all. Verify both figures at GOV.UK — the requirement has changed over time and may change again.

Your State Pension forecast, available through GOV.UK, tells you:

• How many qualifying years you have so far
• What your State Pension forecast is at current State Pension age
• Whether you have gaps and whether they can be filled

State Pension age is currently 66 for both men and women (as of 2026), with planned increases. Verify the current and planned ages at GOV.UK State Pension age.

For more detail on the State Pension itself, see the State Pension guide on Parce — coming soon.