UK National Insurance Calculator (2025/26)
Estimate employee and employer Class 1 National Insurance contributions based on your gross pay.
Assumptions: 2025/26 tax year, Class 1 contributions, standard thresholds and rates. This tool is for estimates only and does not replace payroll software or professional advice.
How this national insurance calculator 2025 works
This calculator is designed for quick, practical estimates of UK Class 1 National Insurance. You enter your gross pay, choose how often that pay is received, and select your employee status. The tool then calculates:
- Estimated employee NI (what is deducted from your pay)
- Estimated employer NI (what your employer pays on top)
- Total NI cost and effective employee NI rate
Behind the scenes, it annualises your pay first, applies yearly NI thresholds, and then converts the result back to your selected period (weekly, monthly, or yearly).
Rates and thresholds used for 2025/26 (estimate model)
For transparency, these are the figures hard-coded in this calculator:
- Primary Threshold (PT): £12,570 per year
- Upper Earnings Limit (UEL): £50,270 per year
- Employee rate (between PT and UEL): 8%
- Employee rate (above UEL): 2%
- Employer secondary threshold: £5,000 per year
- Employer NI rate: 15%
Step-by-step NI formula used
1) Employee National Insurance
For standard employees under State Pension age:
- No employee NI on earnings up to the Primary Threshold.
- 8% on earnings between £12,570 and £50,270.
- 2% on earnings above £50,270.
If you choose “At or above State Pension age,” employee NI is set to £0 in this model.
2) Employer National Insurance
Employer NI is estimated as 15% of annual earnings above £5,000. This is displayed for awareness because it affects total employment cost, even though it is not deducted from your own take-home pay.
Example scenarios
Example A: £3,000 per month, standard employee
Annual gross pay = £36,000. Employee NI is charged at 8% on pay above £12,570 up to £50,270. Employer NI is calculated at 15% above £5,000.
Example B: £1,000 per week, standard employee
Annual gross pay = £52,000. Part of pay falls above the UEL, so employee NI is split: 8% on the main band and 2% on earnings above the upper limit.
Example C: Pension-age worker
In this simplified model, employee NI is £0. Employer NI can still apply above the secondary threshold.
Why NI planning matters in 2025
National Insurance affects both personal cash flow and employer budgeting. A small change in rates or thresholds can materially alter payroll costs over a year. Running scenarios can help you:
- Forecast deductions before accepting a pay rise or bonus
- Compare weekly vs monthly cash impact
- Understand the full employer cost of hiring
- Improve tax and payroll planning confidence
FAQ
Is this an official HMRC calculator?
No. This is an independent estimate tool built for educational use.
Does this include income tax, student loans, or pension deductions?
No. It calculates National Insurance only. For full take-home pay, those items must be added separately.
Does NI always use annual calculations?
Real payroll often operates per pay period with specific HMRC rules. This calculator annualises pay for simplicity, then converts back to your selected frequency.
Can category letters change results?
Yes. Category letters (A, B, C, H, M, Z, etc.) can produce different outcomes. This version models a standard employee case, plus a pension-age option.
Final note
If you need exact payroll deductions, especially for directors, category-letter-specific cases, or mixed pay periods, use HMRC-compliant payroll software or a qualified accountant. For quick estimates, this national insurance calculator 2025 should give you a clear and useful starting point.