What is the UK National Insurance Calculator?
This calculator estimates Class 1 employee National Insurance contributions (NICs) for the United Kingdom based on your annual gross salary. It applies to employees (Category A) and uses HMRC thresholds. Self-employed (Class 2/4) and employer NICs are not covered. Figures are annualised estimates; HMRC applies NI per pay period, so real deductions may differ slightly.
How to use it
Enter your annual gross income and pick a tax year. The main rate is 8% for 2024/25 through 2026/27; the 2023/24 main rate was 12%. All years use a Primary Threshold (PT) of £12,570 and an Upper Earnings Limit (UEL) of £50,270. The result shows total NI plus monthly and weekly breakdowns.
The formula explained
NI is charged at the main rate r₁ on earnings between the PT and the UEL, then at 2% (r₂) on everything above the UEL:
$$\text{NI} = r_{1} \times \left(\min(I,\ \text{UEL}) - \text{PT}\right) + r_{2} \times \max(0,\ I - \text{UEL})$$
Earnings below the PT are NI-free.
Worked example
For a salary of £60,000 in 2024/25: the main band is \(£50{,}270 - £12{,}570 = £37{,}700\), taxed at 8% = £3,016. The upper band is \(£60{,}000 - £50{,}270 = £9{,}730\), taxed at 2% = £194.60. Total NI = £3,210.60 a year, about £267.55 a month.
FAQ
Does this include income tax? No — this only calculates National Insurance, not Income Tax or student loans.
Why did the rate change? The main employee NI rate was cut from 12% to 10% (Jan 2024) and then to 8% (Apr 2024). This tool uses 8% for 2024/25 and all later years as a simplified estimate.
Are these thresholds frozen? The PT (£12,570) and UEL (£50,270) have been frozen for several years; always confirm current rates with HMRC.
