How National Insurance is Calculated in the UK (2026/27)
Updated: March 2026 | 2026/27 Tax Year
National Insurance (NI) is consistently misunderstood. Most people know it's deducted from their pay alongside income tax — but few understand how it's calculated, why there are different classes, and crucially, how it differs from income tax in some surprising ways.
NI Quick Calculator
Estimate your National Insurance deductions for 2026/27. Full breakdown available on our NI Calculator.
£1,794
Your NI (annual)
£150
Your NI (monthly)
£3,574
Employer NI (annual)
Paid on top of your gross
What is National Insurance?
National Insurance is a tax on earnings (for employees) and profits (for the self-employed), collected by HMRC. It funds the NHS, State Pension, and certain state benefits like the Employment and Support Allowance.
Unlike income tax — which funds general government spending — NI is theoretically ring-fenced for social benefits. In practice, both flow into the general Consolidated Fund, but your NI record still directly determines your State Pension entitlement. You need 35 qualifying years of NI contributions for the full new State Pension (£221.20/week in 2026/27).
Employee vs Employer NI by Salary Level
Both contributions grow with salary — but the employer pays significantly more. Note: employer NI is on top of your gross pay.
Class 1 NI: For Employees (2026/27 Rates)
| Band | Annual Earnings | Employee Rate | Employer Rate |
|---|---|---|---|
| Below Lower Earnings Limit | Up to £6,396/yr | 0% | 0% |
| Lower Earnings Limit to Primary Threshold | £6,397 – £12,570/yr | 0% (earns qualifying year) | 0% |
| Primary Threshold to Upper Earnings Limit | £12,571 – £50,270/yr | 8% | 13.8% |
| Above Upper Earnings Limit | Over £50,270/yr | 2% | 13.8% |
* Employee rates fell from 10% to 8% on 6 April 2024 and remain at 8% for 2026/27.
Key Difference: NI is Calculated Weekly/Monthly, Not Annually
This is one of the most important — and most misunderstood — aspects of National Insurance. NI is assessed per pay period, not cumulatively like income tax.
What this means in practice: if you receive a large bonus in October that pushes you above the Upper Earnings Limit in that single month, you pay only 2% on the excess — even if your average annual salary wouldn't have reached the UEL. By contrast, income tax would cumulatively catch up and charge you 40% if you cross the higher rate threshold over the year.
Employee NI Marginal Rate by Salary Band
Rate drops to 2% above the Upper Earnings Limit (£50,270). Income tax at this point is 40% — so NI relief at higher incomes is real but small.
NI vs Income Tax: The Critical Differences
| Feature | Income Tax | National Insurance |
|---|---|---|
| Assessed on | Cumulative annual income | Per pay period (week/month) |
| Charged on pension income? | Yes | No (NI stops at State Pension age) |
| Stops at retirement? | No | Yes — stops when you reach State Pension age |
| Scotland has different rates? | Yes | No — same UK-wide |
| Employer also contributes? | No | Yes — 13.8% on earnings above £9,100/yr |
| Affects State Pension? | No | Yes — builds your qualifying years |
Other NI Classes
- Class 2 (Self-Employed): £3.45/week flat rate if profits > £12,570. Being phased into Class 4 from April 2027.
- Class 4 (Self-Employed): 6% on profits between £12,570–£50,270; 2% above. Paid via Self Assessment.
- Class 3 (Voluntary): £17.45/week — you can pay voluntarily to fill gaps in your NI record and protect your State Pension.
Calculate Your NI
Use our National Insurance Calculator for a precise per-period breakdown. Or use the main UK Salary Calculator to see NI alongside income tax and student loans in one view.