Penalty-exposure calculator

UK CARF penalties are charged per user — £100 for due-diligence failures, £300 where transactions continue without a valid self-certification. Put your numbers in and see what your current gap is theoretically worth. Runs entirely in your browser; nothing is stored.

Total reportable usersUsers on your platform in scope for CARF reporting.Users without a valid self-certificationMissing, invalid or expired self-certs — the number your onboarding history decides.…of whom still transacting (optional)Leave blank to assume all of them — the realistic worst case.

Theoretical exposure, per reporting cycle

£800,000

Due-diligence failures (users without a valid self-certification)SI 2025/744 — £100 per reportable user	2,000 × £100	£200,000
Transactions continuing without a valid self-certificationSI 2025/744 — £300 per user	2,000 × £300	£600,000

Serious breaches (late reporting, record-keeping failures) add up to £5,000 per breach.
Continuing failures add up to £600/day on top.
Theoretical maximum exposure — HMRC may mitigate in practice, but remediation, not mitigation hopes, is the compliance posture.

Provisional counting rules, ruleset v2026.1 — information, not legal or tax advice.

Want this breakdown — plus what actually kills the exposure — by email?

How the penalty regime works, with worked examples: CARF penalties UK. Not sure you're in scope at all? Start with the scope checker.