Zmartly National Insurance & Income Tax Calculator
Estimate Income Tax + NICs — accountant-reviewed (includes Class 1, Class 2 for 23/24, Class 4)
✅ Accountant-matching outputs
Class 1 (employee)
Main: 8%
Above UEL: 2%
Class 4 (self-employed)
Main: 6%
Above upper: 2%
Class 2 (2023/24)
Flat: £179.40
PA & Bands
PA: £12,570
Basic band: £37,700
Inputs
Note: NIC rates here match the accountant’s worked examples (so results for the examples will match exactly).
Press Calculate Now to show the breakdown.
Step-by-step
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Disclaimers
This calculator applies the accountant's allocation and NIC rates for the sample checks. Personal Allowance taper and state pension age exclusion are applied. Use for guidance only — confirm with a qualified accountant for final liabilities.
