What is National Insurance and who has to pay it?
National Insurance Contributions is a tax on earnings that funds the State Pension, the NHS, and benefits like Statutory Maternity Pay. Our national insurance calculator can help you quickly see how much NI you pay based on your income. You pay it if you’re 16 or over and earning above the minimum threshold:
- Employees earning above £12,570/year (Primary Threshold) pay Class 1 NIC
- Self-employed people with profits above £12,570/year (Lower Profits Limit) pay Class 4 NIC
- You stop paying NI when you reach State Pension age, even if you continue working
- Earning below the threshold still builds your NI record and protects your State Pension entitlement
National Insurance rates and thresholds by tax year (2022–2026)
Rates have changed significantly across recent years. Here’s the complete picture:
| Tax Year | Employed Rate | Self-Employed Class 4 | Class 2 NIC | Thresholds (PT / LPL) |
|---|---|---|---|---|
| 2022/23 | 12% (was 13.25% Apr–Nov 2022) | 9.73% / 2.73% | £3.15/week | £12,570 / £11,908 |
| 2023/24 | 10% (cut from 12% Jan 2024) | 8% / 2% | £3.45/week | £12,570 / £12,570 |
| 2024/25 | 8% | 6% / 2% | Abolished | £12,570 / £12,570 |
| 2025/26 | 8% | 6% / 2% | Abolished (Mandatory £3.50/wk) | £12,570 / £12,570 |
Note: The upper rate of 2% applies to all earnings/profits above £50,270 in every year shown.
How Our National Insurance Calculator Works
Our National Insurance calculator uses the latest UK National Insurance thresholds and rates to estimate how much you may pay based on your earnings.
You simply enter your gross annual income (or self-employed profits), and the calculator applies the relevant National Insurance rules for the selected tax year to give an estimate of your contributions.
For employees, it calculates Class 1 National Insurance, which is paid on earnings above the Primary Threshold. For self-employed users, it estimates Class 4 National Insurance, which is based on annual profits above the Lower Profits Limit.
The calculator also takes into account the correct tax year thresholds so you can see when National Insurance starts to apply and how much is charged within each band.
It is designed to give a clear estimate of your National Insurance contributions and how they affect your overall take-home pay. However, your actual liability may vary depending on factors such as multiple employments, salary sacrifice arrangements, or specific HMRC adjustments.
If you want a full breakdown of how tax and National Insurance affect your earnings, you can also use our salary after tax calculator to see your exact take-home pay instantly.
How did National Insurance change in 2024, 2025 and 2026?
In 2024–25, which brought the biggest set of NI cuts in a generation:
- The employee main rate fell from 12% to 8% on earnings between £12,570 and £50,270, saving an average earner around £750/year
- The self-employed Class 4 main rate dropped from 9% to 6%
- Mandatory Class 2 NIC was abolished from 6 April 2024. Self-employed people no longer pay a flat weekly rate
In 2025–26:
- Rates and thresholds remain frozen with no cuts and no increases either
- Voluntary Class 2 NIC (for topping up your State Pension) rose slightly to £3.50/week
- The freeze means more earners gradually get pulled into paying NI as wages rise above frozen thresholds
Example: how is National Insurance calculated?
Scenario: Self-employed with £55,000 turnover and £12,000 allowable expenses in 2024–25.
- Taxable profit: £55,000 − £12,000 = £43,000
- Amount in main band: £43,000 − £12,570 = £30,430
- Class 4 (main rate): £30,430 × 6% = £1,825.80
- Class 4 (upper rate): profit is below £50,270, so £0.00
- Class 2: abolished in 2024, so £0.00
- Total NIC: £1,825.80
The same profit in 2022–23 would have cost around £3,050 including Class 2, a saving of over £1,200 a year.
How do I calculate NI for previous tax years?
The key is using the correct rates and thresholds for the exact year you need. The most common mistakes are applying current rates to old years, or missing the fact that 2022–23 had a unique Lower Profits Limit of £11,908 for the self-employed (not £12,570). Our national insurance calculator applies the correct figures automatically when you select the right year.
For 2022–23 specifically, there were rate changes mid-year (6 April, 6 July, and 6 November). Our national insurance calculator uses the simplified annual equivalent, so it’s best used as an estimate for that year rather than a precise figure.
How do I pay National Insurance?
Employed: Your employer deducts Class 1 NIC automatically through PAYE before your wages reach you. No action needed.
Self-employed: You pay Class 4 NIC through your annual Self Assessment tax return. The deadline is 31 January following the end of the tax year.
Gaps in your record: If you have years where you didn’t pay enough NI, you can make voluntary Class 3 contributions (£17.75/week in 2025–26) to protect your State Pension. Generally worth doing if you’re within 15 years of retirement.
Check your full NI record and State Pension forecast by logging in to your personal tax account at gov.uk.
This national insurance calculator provides estimates only and is not personalised tax advice. Figures assume a full tax year of contributions. Always check your position with HMRC or a qualified accountant.