National Insurance is one of those deductions that appears on every payslip but most people never fully understand. They know it takes money from their wages. They vaguely know it relates to the NHS and pensions. Beyond that, it remains a mystery — which is a problem because National Insurance contributions directly determine whether you qualify for the state pension and certain benefits.

This guide explains what National Insurance actually is, who pays it, how much you pay at different income levels, the different classes, and what you get in return.

What Is National Insurance?

National Insurance (NI) is a tax on earnings and profits. Despite the name, it is not insurance in the traditional sense — you do not get a policy or make a claim. It is a compulsory contribution that funds specific parts of the UK welfare system.

National Insurance contributions fund the state pension, Jobseeker's Allowance, Employment and Support Allowance, Maternity Allowance, and Bereavement Support Payment. They do not directly fund the NHS — that comes primarily from general taxation — although NI was originally designed to cover healthcare costs and the link persists in the public imagination.

The key difference between National Insurance and income tax is that NI contributions build your entitlement to certain benefits. If you have not paid enough NI over your working life, you may receive a reduced state pension or no state pension at all. Income tax, by contrast, does not create any personal entitlement — it simply funds government spending.

Who Pays National Insurance?

Almost everyone who works in the UK pays National Insurance in some form.

Employees pay Class 1 NI, which is deducted automatically from their wages by their employer before the money reaches their bank account. It appears on the payslip alongside income tax under PAYE.

Employers also pay NI on each employee's wages. This is a separate charge on top of what the employee pays. It does not appear on the employee's payslip — it is an additional cost to the business.

Self-employed people pay Class 2 and Class 4 NI through their annual self-assessment tax return. The rates and thresholds are different from employed NI.

Voluntary contributors can pay Class 3 NI to fill gaps in their record if they have years where they did not pay enough to qualify. This is common for people who took time off work for caregiving, illness, or living abroad.

You stop paying NI when you reach state pension age, even if you continue working. Income tax, however, continues regardless of age.

National Insurance Classes

There are several classes of NI, each applying to different situations.

Class 1 (Employees)

This is the most common type. If you are employed, you pay Class 1 NI on your earnings above the Primary Threshold. Your employer pays a separate Class 1 contribution on your earnings above the Secondary Threshold.

Employee rate: 8% on earnings between the Primary Threshold and the Upper Earnings Limit. 2% on earnings above the Upper Earnings Limit.

Employer rate: 13.8% on earnings above the Secondary Threshold. There is no upper limit — employers pay 13.8% on all earnings above the threshold.

Class 2 (Self-employed)

A flat weekly rate paid by self-employed people with profits above the Small Profits Threshold. Class 2 contributions count toward your state pension qualifying years.

Rate: A small flat weekly amount. If your profits are below the threshold, you can choose to pay voluntarily to protect your pension record.

Class 3 (Voluntary)

Voluntary contributions to fill gaps in your NI record. Useful if you have years where you did not work, worked abroad, or earned below the threshold. Each year of Class 3 contributions adds one qualifying year toward your state pension.

Rate: A weekly amount significantly higher than Class 2. The cost is fixed regardless of your income.

Class 4 (Self-employed profits)

Paid by self-employed people on profits above the Lower Profits Limit. This is the main NI charge for the self-employed, similar to Class 1 for employees but at a different rate.

Rate: 6% on profits between the Lower Profits Limit and the Upper Profits Limit. 2% on profits above the Upper Profits Limit.

Class 4 contributions do not count toward benefit entitlements — they are essentially a profits tax. Your state pension entitlement comes from Class 2.

How Much Do You Pay? (Worked Examples)

These examples show the real NI cost at different salary levels for employees.

Earning £20,000 per year

Earnings above the Primary Threshold are subject to 8% NI. Below the threshold, you pay nothing.

Assuming a Primary Threshold of approximately £12,570 per year, your NI-liable earnings are £7,430. At 8%, you pay approximately £594 per year, or £49.50 per month.

Earning £30,000 per year

NI-liable earnings: approximately £17,430. At 8%, you pay approximately £1,394 per year, or £116 per month.

Earning £50,000 per year

NI-liable earnings below the Upper Earnings Limit are taxed at 8%. Earnings above the Upper Earnings Limit (approximately £50,270) are taxed at 2%.

At this salary, virtually all your NI is at 8%. You pay approximately £2,994 per year, or £250 per month.

Earning £80,000 per year

Earnings up to the Upper Earnings Limit: 8% on approximately £37,700 = £3,016. Earnings above the Upper Earnings Limit: 2% on approximately £29,730 = £595. Total: approximately £3,611 per year, or £301 per month.

The 2% rate above the Upper Earnings Limit means that NI becomes proportionally less as your earnings increase — unlike income tax, which stays at the same marginal rate. This makes NI slightly regressive at higher incomes.

Self-employed earning £40,000 profit

Class 2: A small flat weekly rate, totalling roughly £160 to £180 per year.

Class 4: 6% on profits between the Lower Profits Limit and the Upper Profits Limit. On £40,000 profit, this is approximately £1,650 per year.

Total self-employed NI: approximately £1,810 to £1,830 per year. Significantly less than an employee earning the same amount, which is one of the tax advantages of self-employment.

Our percentage calculator can help you work out what percentage of your gross salary goes to NI versus income tax versus take-home pay.

National Insurance and Your State Pension

This is the part most people do not understand — and it is arguably the most important.

To receive the full new state pension, you need 35 qualifying years of NI contributions. To receive any state pension at all, you need a minimum of 10 qualifying years. A qualifying year is one in which you either paid enough NI through employment or self-employment, received NI credits (for example, while claiming certain benefits or caring for a child under 12), or made voluntary Class 3 contributions.

The full new state pension is currently over £11,500 per year. If you have fewer than 35 qualifying years, your pension is reduced proportionally. Someone with 25 qualifying years would receive roughly 25/35 of the full amount.

How to check your NI record

Go to gov.uk and search for "check your National Insurance record." You can log in with your Government Gateway ID and see exactly how many qualifying years you have, which years have gaps, and how much voluntary contribution would cost to fill each gap.

This is one of the most valuable five minutes you can spend on your finances. Many people discover gaps they did not know about — years abroad, years of low earnings, or years where credits were not applied correctly.

Is it worth filling gaps?

Almost always yes. A single year of voluntary Class 3 contributions currently costs roughly £800 to £900. In return, you receive an additional 1/35 of the full state pension — approximately £330 per year — for the rest of your life from state pension age. If you live even three years past pension age, you have more than recouped the cost. Over a typical retirement of 20 or more years, the return is exceptional.

You can usually fill gaps going back six years. Beyond that, special rules may apply. Check your record and act sooner rather than later — the opportunity to fill older gaps eventually expires.

National Insurance Credits

You do not always need to pay NI to get a qualifying year. In certain situations, you receive NI credits automatically.

Child Benefit: If you are registered for Child Benefit for a child under 12, you receive NI credits for each year. This applies even if you do not actually receive the payment because of the High Income Child Benefit Charge. Many higher-earning families opt out of receiving the payment but should still register to protect the non-working parent's NI record.

This is a frequently missed detail. If one parent stays home with children and the other earns above the threshold, the stay-at-home parent should still register for Child Benefit to receive NI credits. Not doing so creates gaps that reduce their future state pension.

Jobseeker's Allowance and Employment and Support Allowance: Claiming these benefits automatically provides NI credits.

Carer's Allowance: If you are caring for someone for at least 20 hours per week, you receive NI credits.

Universal Credit: In many cases, receiving Universal Credit provides NI credits, though the rules are complex and depend on your specific circumstances.

Grandparent credits

If a grandparent provides childcare for a grandchild under 12 while the parent works, the parent can transfer their NI credit to the grandparent. This is called Specified Adult Childcare Credits. It is little-known but can be valuable for grandparents who have gaps in their NI record.

National Insurance for the Self-Employed

Self-employed NI works differently from employee NI in important ways.

You pay both Class 2 and Class 4, but the total is significantly less than the combined employee and employer Class 1 contributions on the same income. This is one reason why self-employment can be more tax-efficient than employment — though you lose employer pension contributions, sick pay, and other employment benefits.

Class 2 contributions are what qualify you for the state pension. If your profits are very low, you may not be required to pay Class 2 — but you can choose to pay voluntarily to protect your pension record. Given the exceptional return on voluntary contributions (as explained above), this is almost always worth doing.

Class 4 contributions are essentially a profits tax and do not build entitlement to any specific benefit.

Self-employed NI is calculated and paid through your annual self-assessment tax return. Our freelancer tax guide covers the full self-assessment process including NI.

National Insurance and Employment Decisions

Understanding NI helps you make better decisions about employment structure.

Salary sacrifice: Some employers offer salary sacrifice schemes for pension contributions, childcare vouchers, or cycle-to-work schemes. When you sacrifice salary, both you and your employer pay less NI on the sacrificed amount. This makes salary sacrifice more tax-efficient than contributing from net pay.

For example, if you sacrifice £500 per month into your pension instead of taking it as salary, you save 8% NI (£40) and your employer saves 13.8% (£69). Some employers pass their NI saving back to you by increasing the pension contribution further. Always ask whether this is the case.

Dividend vs salary for company directors: Company directors who own their business often pay themselves a small salary (up to the Primary Threshold to avoid NI but still qualify for a NI year) and take the rest as dividends. Dividends are not subject to NI, making this structure more tax-efficient than a pure salary. The optimal salary and dividend split changes with each tax year's thresholds.

Employment vs self-employment: Employees pay 8% NI on earnings. Self-employed people pay 6% Class 4 plus a small Class 2 amount. The self-employed rate is lower, but this must be weighed against the loss of employer NI contributions to your pension, statutory sick pay, and other employment protections.

Common Questions

Do I pay NI after state pension age?

No. Once you reach state pension age, you stop paying employee NI and self-employed NI, even if you continue working. You do still pay income tax on your earnings.

Can I opt out of National Insurance?

No. NI is compulsory on all qualifying earnings and profits. The only way to avoid it is to earn below the threshold.

Does NI pay for the NHS?

Not directly. The NHS is funded primarily through general taxation, not NI specifically. However, some NI revenue is allocated to the NHS via the National Insurance Fund, and the Health and Social Care Levy (introduced and then reversed) was an NI surcharge explicitly for health funding. The relationship between NI and healthcare is politically complex and historically muddled.

What happens to NI I have already paid?

It builds your entitlement record. You cannot get a refund of NI contributions (except in very specific overpayment situations). The return on your contributions comes in the form of state pension and benefit eligibility.

Is National Insurance going up or down?

NI rates have changed multiple times in recent years and will likely change again. The thresholds and rates in this guide are based on current rules. Check gov.uk for the most up-to-date figures, particularly after each Spring Statement or Autumn Budget.

Final Thoughts

National Insurance is not exciting. It is not the topic people choose to read about on a Saturday evening. But understanding it protects thousands of pounds of state pension income that you might otherwise lose through ignorance, fills gaps in your record before they become permanent, and helps you make smarter decisions about salary sacrifice, self-employment structure, and retirement planning.

Check your NI record today at gov.uk. It takes five minutes. If there are gaps, fill them. If you are self-employed, make sure you are paying Class 2. If you are a parent registered for Child Benefit, ensure the credits are going to the right person.

These small administrative actions have a disproportionately large impact on your financial security decades from now.

Last updated: March 2026. NI rates and thresholds are based on current HMRC guidelines and may change with future budgets. Always verify current figures at gov.uk. This article is for informational purposes only and does not constitute financial or tax advice.