Income Tax vs National Insurance Calculator: Complete Tax Breakdown
Understand how income tax and national insurance are calculated separately in your payslip.
By Calculator Team•9 min read•
Income Tax vs National Insurance: Breaking Down Your Payslip
Your payslip shows various deductions, but two of the biggest are income tax and National Insurance. They're separate calculations, serve different purposes, but both affect your take-home pay. Understanding each helps you plan your finances more accurately.
Income Tax
Income tax funds general government spending: schools, healthcare, infrastructure, defense, and more.
How it works:
- Progressive brackets: 0%, 20%, 40%, 45%
- Most earners pay 20% on income between £12,570 and £50,270
- No tax on personal allowance (first £12,570)
National Insurance
National Insurance funds specific state benefits: pensions, unemployment benefits, sickness benefits, and healthcare.
How it works:
- Different rates for employees (8%) and self-employed (9%)
- Lower threshold: starts around £12,570
- Upper rate applies to earnings over £50,270
Key Differences
| Aspect | Income Tax | National Insurance |
|---|---|---|
| Purpose | General government | Specific state benefits |
| Top Rate | 45% | 8-10% |
Combined Impact on Your Salary
Earn £50,000? You're paying roughly 20% income tax + 8% National Insurance = 28% total. This is why understanding both is crucial for accurate take-home pay calculations.