If HMRC reclassifies your self-employed operatives as employees, the firm that paid them owes Employer NI, Employee NI (the delta between Class 4 paid on self-assessment and Class 1 that should have been deducted), plus interest and penalties. Verified 2026/27 rates.
Current headcount engaged under CIS, not PAYE
Before CIS deduction. Typical UK site rates £600–£1,800
46–50 is standard. Reduce for seasonal trades
HMRC standard: 4 (carelessness discovered), 6 (careless error) or 20 (deliberate). Enter any value.
HMRC-assessed conduct loading, applied to the NI shortfall
Your potential total HMRC liability
£0
Per-operative exposure: £0
Employer National Insurance Liability£0
Employee National Insurance Liability£0
Fines, Penalties & Interest£0
Your Potential Total HMRC Liability£0
Gross pay per operative per year£0
Total gross pay (all operatives, all years)£0
Employer NI at 15% (above £5,000/op/yr threshold)£0
Employee NI at 8% (above £12,570/op/yr threshold)£0
HMRC simple interest at 7.75% (averaged over reach-back)£0
Behaviour penalty£0
TOTAL£0
What's included: Employer Class 1 NI at 15% above £5,000/op/year, Employee Class 1 NI at 8% above £12,570/op/year, HMRC simple interest at 7.75% (the current late payment rate from 9 January 2026), and a behaviour-based penalty.
What's NOT included: PAYE income tax, on the basis that a CIS subcontractor normally files self-assessment and pays income tax directly – HMRC does not double-recover income tax already paid by the worker. Also excluded: apprenticeship levy, CITB levy, holiday pay back-claims (a separate Employment Tribunal risk, not a tax liability). In exceptional cases where the worker had not paid self-assessment tax, HMRC can recover income tax from the employer under Regulation 72 ITEPA 2003 – a further ~20-25% exposure on top of the figures shown.
