National Insurance Explained

National Insurance (NI) is one of the UK's most misunderstood taxes. Despite its name suggesting an insurance scheme, it functions as a payroll tax — automatically deducted from your pay alongside income tax. This guide explains what NI is, why you pay it, how it's calculated, and what you get in return.

What National Insurance Funds

NI contributions fund specific parts of the welfare state:

State Pension: The single largest NI expenditure. Your contributions build your entitlement to the State Pension when you retire.
NHS: A proportion of NI funds the National Health Service, though most NHS funding comes from general taxation.
Statutory benefits: Statutory Sick Pay, Maternity Allowance, Bereavement Support Payment, and contribution-based Jobseeker's Allowance and Employment and Support Allowance.

Unlike income tax (which goes into the general government pot), NI is nominally ring-fenced for these purposes through the National Insurance Fund. In practice, the distinction is increasingly blurred, and Treasury effectively manages both.

NI Classes Explained

There are several classes of NI, each applying to different groups:

Class	Who Pays	How It's Paid
Class 1 (Employee)	Employees earning above £12,570/year	Deducted from pay via PAYE
Class 1 (Employer)	Employers on employees' earnings above £5,000/year	Paid by employer to HMRC
Class 2	Self-employed with profits above £12,570/year	Paid through Self Assessment
Class 3	Voluntary contributions to fill gaps	Paid directly to HMRC
Class 4	Self-employed with profits above £12,570/year	Paid through Self Assessment

Class 1 NI Rates for Employees 2026/27

Earnings Band	Annual Range	Employee Rate
Below Lower Earnings Limit	Up to £6,708	0% (no pension credit)
LEL to Primary Threshold	£6,708 – £12,570	0% (pension credit earned)
Primary Threshold to UEL	£12,570 – £50,270	8%
Above Upper Earnings Limit	Over £50,270	2%

The distinction between the LEL and PT is important: if you earn between £6,708 and £12,570, you don't pay any NI but you're treated as having paid it. This protects your State Pension record without costing you anything.

NI and Your State Pension

Your NI record directly determines your State Pension entitlement:

35 qualifying years = full new State Pension (currently £221.20/week, £11,502/year).
10 qualifying years = minimum to get any State Pension.
Between 10 and 35 years: You get a proportional amount (e.g., 25 years = 25/35 of full pension).

A qualifying year is one where you either earned above the LEL, paid Class 2 NI, or received NI credits (e.g., while claiming Universal Credit, Child Benefit for a child under 12, or Carer's Allowance).

Checking Your NI Record

You can check your NI record online at GOV.UK. It shows:

How many qualifying years you have.
Any gaps in your record.
Your forecast State Pension amount.
Whether you can fill gaps with voluntary Class 3 contributions.

Filling Gaps with Voluntary Contributions

If you have gaps in your NI record (due to living abroad, being unemployed, or earning below the LEL), you can pay voluntary Class 3 contributions to fill them. The cost is £17.45 per week (£907.40 per year for 2026/27). Each additional qualifying year increases your State Pension by approximately £329 per year — making voluntary contributions excellent value if you're short of 35 years.

You can usually fill gaps from the last 6 years. There's currently an extended deadline allowing gaps back to 2006/07 to be filled — but this deadline is expected to close soon. Check GOV.UK for the current deadline.

NI When You Reach State Pension Age

Once you reach State Pension age, you stop paying employee NI entirely — even if you continue working. Your employer still pays employer NI on your wages, but nothing is deducted from your pay. This effectively gives you a pay rise of 8% (or 2% if you earn above the UEL) on the day you reach State Pension age.

The current State Pension age is 66 for both men and women. It's scheduled to increase to 67 between 2026 and 2028, and to 68 between 2044 and 2046 (subject to government review).

NI vs Income Tax: Key Differences

Feature	Income Tax	National Insurance
Applies to	All income types	Employment/self-employment only
Rate direction	Increases with income	Decreases (8% → 2%)
Personal allowance taper	Yes (above £100k)	No
Age limit	Payable at any age	Stops at State Pension age
Benefit entitlement	No	Builds pension/benefit rights
Calculation basis	Cumulative (annual)	Per pay period

Calculators

National Insurance Calculator — See your NI breakdown
Salary Calculator — Full take-home pay with NI
Pension Calculator — See NI savings from salary sacrifice