Stay ahead of deadlines. Filing alerts for UK accountants.
Stop manually tracking deadlines. PenaltyProof monitors registered clients' Companies House, VAT, Corporation Tax, and payroll obligations — emailing you 30 days, 14 days, and 7 days before each due date. Free for up to 5 companies, no card required.
What filings do UK companies have to make?
Every UK limited company and LLP registered at Companies House must file two types of document annually:
Confirmation statement — confirms that the information Companies House holds about your client is accurate. Due within 14 days of the company's confirmation date (which falls on the anniversary of incorporation or the last filed confirmation statement). The filing fee is £34 online.
Annual accounts — financial statements showing the company's trading position. Private limited companies must file within 9 months of their accounting reference date. Public companies have 6 months. Late filing penalties start at £150 for private companies and escalate sharply the longer the delay continues.
What happens when a client misses a deadline?
Companies House issues automatic late filing penalties without warning. For private companies, annual accounts penalties are: £150 (up to 1 month late), £375 (1–3 months), £750 (3–6 months), £1,500 (over 6 months). A company that files late in two consecutive years has its penalty doubled. Confirmation statement failures can result in the company being struck off the register.
How PenaltyProof helps accountants
PenaltyProof reads the public Companies House API once a day for every company number on your list. Free accounts receive Companies House advance alerts 30 days, 14 days, and 7 days before each filing deadline, plus an overdue alert if anything is missed. Starter and Pro accounts also receive advance alerts for HMRC obligations — VAT, Corporation Tax, payroll, Self Assessment, and MTD ITSA. One account covers your entire client list — no per-company registration required.
The service is free for up to 5 companies. The Starter plan covers up to 50 companies for £29/month. Pro covers unlimited companies for £39/month.
Start monitoring your client list today
Full Starter access for 30 days. No contracts, cancel any time.
Start 30-day free trialor try the free plan (up to 5 companies, no card).
Reviews as they come in.
PenaltyProof is new. We are in early access and collecting feedback from the first practices through the door. When customers share quotes, we will publish them here verbatim — no star inflation, no summary counts.
Using PenaltyProof? We want to hear from you.
Email hello@penaltyproof.co.uk with your experience. What was the first deadline you caught? What would you tell another accountant?
Find the right plan for your practice
Different practices have different needs. We have segment-specific guides for the two most common shapes:
Frequently asked questions
Does PenaltyProof access my clients' financial data?
No. PenaltyProof only reads publicly available data from the official Companies House API — the same information visible on the Companies House website. No accounting software access, no HMRC data, no client financials are ever involved. For a detailed breakdown of what data we hold and your obligations under UK GDPR, see our guide on Companies House monitoring and GDPR for accountants.
Which filing types does it track?
Confirmation statements and annual accounts for UK Companies House-registered entities — limited companies and LLPs. HMRC deadline monitoring — including VAT returns, Corporation Tax, RTI FPS, P11D and Class 1A NIC, SA secondary dates, MTD ITSA, and ECCTA IDV — is available on paid plans.
How do I add or remove clients?
Visit the manage page — we'll send a secure link to your registered email. Use it to add or remove company numbers at any time. No password required.