National Insurance

What Is National Insurance?

National Insurance (NI) is a mandatory payroll contribution in the United Kingdom, paid by both employees and employers (and the self-employed). It funds the State Pension, the NHS, maternity pay, unemployment (Jobseeker’s Allowance), and other state benefits.

Despite its name, National Insurance is effectively a second income tax — it is calculated as a percentage of earnings, collected through the same PAYE system as income tax, and contributes to the same Treasury pool. The main practical difference is that NI generates eligibility for contributory benefits.

Rates for Employees (Class 1) — 2026/27

Earnings	NI Rate
Up to £12,570 (Primary Threshold)	0%
£12,571 – £50,270	8%
Above £50,270 (Upper Earnings Limit)	2%

Note: The Primary Threshold aligns with the income tax personal allowance at £12,570, so NI and income tax both start at the same level of earnings.

Employer Contributions (Secondary Class 1)

Employers pay NI on top of the employee’s gross salary:

Earnings	Employer NI Rate
Up to £9,100 (Secondary Threshold)	0%
Above £9,100	15%

This 15% employer rate is a significant cost on top of salary — someone earning £50,000 costs their employer approximately £56,000 all-in before any other benefits. The employer NI is not deducted from the employee’s pay but adds to the total employment cost.

Worked Example: Employee at £45,000 (2026/27)

Item	Calculation	Amount
Income tax	20% × (£45,000 − £12,570)	£6,486
NI (employee)	8% × (£45,000 − £12,570)	£2,594
Total deductions		£9,080
Take-home pay	£45,000 − £9,080	£35,920

Effective income tax rate: 14.4%. Effective combined rate (tax + NI): 20.2%.

Self-Employed: Class 2 and Class 4

Self-employed individuals pay different NI classes:

Class 2: A flat weekly charge (£3.45/week in 2026/27) payable if profits exceed £12,570. In 2024 HMRC effectively abolished the charge while preserving benefit entitlement for most self-employed people, though the detailed rules continue to evolve.

Class 4: Earnings-related NI on self-employment profits:

• 6% on profits between £12,570 and £50,270
• 2% on profits above £50,270

The Class 4 rates are slightly lower than employee Class 1 rates (6% vs 8% in the main band), reflecting that the self-employed do not receive employer contributions and have reduced benefit entitlements.

NI Qualifying Years and the State Pension

Your entitlement to the UK State Pension depends on your qualifying National Insurance years. You need:

• 35 qualifying years for the full new State Pension (currently £11,502/year)
• 10 qualifying years minimum for any State Pension

A qualifying year is one in which you paid enough NI contributions (or received NI credits through unemployment, caring, or other qualifying reasons).

Gaps in your NI record — from time abroad, career breaks, or periods of low income — can be filled by making voluntary Class 3 NI contributions (£17.45/week in 2026/27). Given the value of the State Pension over a typical retirement, voluntary top-ups are often excellent value.

NI and the Combined Marginal Rate

NI substantially raises marginal rates at certain income levels, creating the famous UK “combined” rates:

Income Range	Income Tax	NI (employee)	Combined
£0 – £12,570	0%	0%	0%
£12,571 – £50,270	20%	8%	28%
£50,271 – £100,000	40%	2%	42%
£100,001 – £125,140	60%*	2%	62%
Above £125,140	45%	2%	47%

*The 60% effective rate in the £100,000–£125,140 band arises from the withdrawal of the personal allowance (losing £1 of allowance for every £2 of income above £100,000).

Salary Sacrifice and NI Savings

Because employer NI is charged on gross salary, arrangements that reduce the gross salary — such as salary sacrifice into pensions or cycle-to-work schemes — save both employee NI and employer NI. An employer who redirects their NI savings into the employee’s pension can significantly boost retirement savings at no net cost.

For example, contributing £500/month into a pension via salary sacrifice rather than net pay saves:

• Employee: 8% NI on £500 = £40/month
• Employer: 15% on £500 = £75/month (often passed on as additional pension contributions)
• Plus income tax relief on the full £500

History and Context

National Insurance was introduced in 1911 by Lloyd George to fund sickness and unemployment benefits. It was expanded by the Beveridge Report in 1942 and the National Insurance Act 1946, which created the NHS and the modern welfare state.

Over decades, successive governments have raised NI rates, lowered thresholds, and expanded the base, blurring the line between NI and income tax. The 2022 Health and Social Care Levy proposal (which would have formally separated NI from its contributory basis) was withdrawn after political controversy.

Key Takeaway

National Insurance adds significantly to the UK tax burden — typically 8–10 percentage points on top of income tax for workers in the basic-rate band. Understanding the combined rate (income tax + NI) gives a much more accurate picture of your actual marginal and effective rates than income tax alone. Use the UK income tax calculator for full take-home calculations including National Insurance.