UK National Insurance Contributions Calculator

Calculate your UK National Insurance Contributions (NICs) for the 2024/25 tax year based on your employment status and earnings.

Formulas Used (2024/25 Tax Year)

Employee (Class 1 Primary NIC):

  • 0% on earnings up to the Primary Threshold (PT): £12,570/year
  • 8% on earnings between PT and Upper Earnings Limit (UEL): £12,570 – £50,270/year
  • 2% on earnings above UEL: £50,270+/year

Employer (Secondary Class 1 NIC):

  • 0% on employee earnings up to Secondary Threshold (ST): £9,100/year
  • 13.8% on employee earnings above ST: £9,100+/year

Self-Employed (Class 4 + Class 2):

  • Class 4: 0% up to Lower Profits Limit (LPL) £12,570
  • Class 4: 6% between LPL and Upper Profits Limit (UPL) £12,570 – £50,270
  • Class 4: 2% above UPL £50,270+
  • Class 2: £3.45/week (£179.40/year) if profits ≥ Small Profits Threshold (£12,570)

Effective Rate = (Total Annual NIC ÷ Annual Gross Income) × 100

Assumptions & References

  • All thresholds and rates are based on the 2024/25 UK tax year (6 April 2024 – 5 April 2025).
  • Employee Class 1 Primary NIC rate was reduced from 10% to 8% effective 6 April 2024.
  • Self-Employed Class 4 NIC rate was reduced from 8% to 6% effective 6 April 2024.
  • Class 2 NICs for self-employed are treated as paid via Self Assessment if profits ≥ Small Profits Threshold; voluntary Class 2 contributions (£3.45/week) can be made if profits are below SPT.
  • This calculator does not account for Employment Allowance (up to £5,000 off employer NICs), Married Women's Reduced Rate, or deferment arrangements.
  • Income is assumed to be from a single source with no other NIC-affecting factors.
  • Monthly figures = Annual ÷ 12; Weekly figures = Annual ÷ 52.
  • Source: GOV.UK — National Insurance rates and categories
  • Source: HMRC NIC rates

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