National Insurance is one of the biggest deductions from most UK workers’ payslips — yet many people confuse it with income tax or have little idea what it actually funds. This guide explains what National Insurance is, what you pay, and why it matters for your financial future.
What Is National Insurance?
National Insurance (NI) is a contributory benefit system. Unlike income tax, which funds general government spending, NI contributions are specifically ring-fenced for social security purposes.
Your NI contributions help fund:
- State Pension — Your NI record determines how much State Pension you receive
- Jobseeker’s Allowance — Contribution-based benefits for unemployment
- Statutory sick pay — Payment during periods of illness
- Maternity, paternity, and adoption pay — Statutory payments during family leave
- Bereavement support payment — Financial support following a partner’s death
To qualify for these benefits, you need a sufficient NI record. The number of qualifying years you have built up directly affects your entitlement.
Class 1: Employed Contributors
If you are employed, you and your employer both pay Class 1 NI. This is the most common type and is deducted automatically through payroll.
Employee Rates (2024/25)
| Earnings Band | Annual | Rate |
|---|---|---|
| Below primary threshold | Up to £12,570 | 0% |
| Between primary and upper earnings limit | £12,570 - £50,270 | 8% |
| Above upper earnings limit | Above £50,270 | 2% |
Employer Rates (2024/25)
| Earnings Band | Annual | Rate |
|---|---|---|
| Below secondary threshold | Up to £9,100 | 0% |
| Above secondary threshold | Above £9,100 | 13.8% |
Key points about Class 1 NI:
- NI is calculated on gross (pre-tax) income, before income tax is deducted
- Employer NI is paid by your employer on top of your salary — you do not pay this directly, but it affects how much employers are willing to offer
- NI contributions stop when you reach State Pension age
- Unlike income tax, there is no personal allowance equivalent within NI — you start paying from the first pound above the threshold
Class 2: Self-Employed Contributors
If you are self-employed, you may need to pay Class 2 NI to maintain your NI record and protect your entitlement to certain benefits.
Class 2 Rates (2024/25)
- Flat rate: £3.45 per week (approximately £179 per year)
- Threshold: Payable if your annual profits exceed £12,570
- Voluntary: If profits are below the threshold, you can voluntarily pay Class 2 NI to protect your record
Class 2 NI is relatively cheap and is the main way self-employed people maintain their NI record for State Pension purposes. If you do not pay Class 2 NI and do not have enough qualifying years, you may receive a reduced State Pension.
Class 4: Self-Employed Profits
Class 4 NI is charged on self-employed profits and is separate from Class 2.
Class 4 Rates (2024/25)
| Profits Band | Annual | Rate |
|---|---|---|
| Below lower profits limit | Up to £12,570 | 0% |
| Between lower and upper profits limit | £12,570 - £50,270 | 9% |
| Above upper profits limit | Above £50,270 | 2% |
Class 4 is calculated through your Self Assessment tax return and is deducted alongside income tax. It does not count towards your NI record for benefit entitlement — that is what Class 2 is for.
NI Credits
NI credits are a way of building up your NI record when you are not paying contributions. You automatically receive credits in certain circumstances:
- Caring for someone — If you are a carer receiving Carer’s Allowance
- Unemployed and claiming benefits — If you are receiving Jobseeker’s Allowance or Employment and Support Allowance
- Sick or disabled — If you are receiving Statutory Sick Pay or Incapacity Benefit
- Parental leave — If you are on maternity, paternity, or adoption leave
- Jury service — Automatic credits during jury service periods
NI credits are particularly important if you have gaps in your employment history. Without enough qualifying years, your State Pension will be reduced.
State Pension and NI
Your NI record is the key to your State Pension. The full new State Pension (2026/27) is £221.20 per week — but you need 35 qualifying years to receive the full amount.
Qualifying Years
A qualifying year is any year in which you:
- Paid enough Class 1, 2, or 4 NI
- Received NI credits
- Paid voluntary NI contributions
If you have fewer than 35 qualifying years, your State Pension is reduced proportionally. With fewer than 10 qualifying years, you receive nothing.
Check Your NI Record
You can check your NI record and projected State Pension at gov.uk/check-state-pension. This shows:
- Your NI record year by year
- How many qualifying years you have
- Your projected State Pension amount
- Any gaps in your record
Voluntary NI Contributions
If you have gaps in your NI record, you can pay voluntary contributions to fill them. This can be particularly valuable if you are close to State Pension age and do not have enough qualifying years.
Voluntary Contribution Classes
- Class 3: Voluntary contributions at £17.75 per week (approximately £923 per year)
- Class 2: Voluntary contributions at £3.45 per week for self-employed people with gaps
Rules for Voluntary Contributions
- You can normally backfill gaps for up to 6 years
- After 6 years, it may still be possible to pay but you will need to contact HMRC
- The cost of voluntary contributions is usually much less than the value of the additional State Pension they generate
- Voluntary contributions are a personal financial decision — consider your expected longevity and other pension provisions
Worked Example: Employed, £40,000 Salary
Let us calculate the NI for someone earning £40,000 per year.
Employee NI (Class 1):
- Earnings between £12,570 and £40,000: £27,430
- 8% of £27,430 = £2,194 per year (approximately £183 per month)
Employer NI (Class 1):
- Earnings above £9,100: £30,900
- 13.8% of £30,900 = £4,264 per year
You do not pay employer NI directly, but it is worth understanding because it affects the total cost of employment and can influence salary negotiations and benefits packages.
Total NI on a £40,000 salary:
- Employee: £2,194 per year
- Employer: £4,264 per year
- Combined: £6,458 per year
Common Mistakes
- Confusing NI with income tax — NI is a separate deduction with different rates and thresholds
- Ignoring gaps in your NI record — Unpaid gaps reduce your State Pension and may affect benefit entitlement
- Not checking your record regularly — Errors can go undetected for years
- Assuming employer NI affects your pay — Employer NI is paid by your employer on top of your salary, not deducted from it
- Forgetting to pay voluntary contributions — If you have gaps and are close to retirement, voluntary NI can be excellent value
Tips for Maximising Your NI Position
- Check your NI record on gov.uk — Identify any gaps and understand how many qualifying years you have
- Pay voluntary contributions if you have gaps — Particularly if you are within 10 years of State Pension age
- Protect your State Pension — Ensure you have 35 qualifying years for the full amount
- Understand the difference between Class 1, 2, and 4 — Each serves a different purpose
- Keep records of self-employment — Ensure you are paying the correct Class 2 and Class 4 contributions
- Do not confuse NI with income tax — They are calculated separately with different thresholds
- Consider NI when negotiating salary — Employer NI costs affect what employers can offer
Resources
- GOV.UK Check Your NI Record: www.gov.uk/check-national-insurance-record
- HMRC National Insurance: www.gov.uk/national-insurance
- MoneyHelper NI Guide: www.moneyhelper.org.uk
- GOV.UK State Pension Forecast: www.gov.uk/check-state-pension