Free plan — up to 5 companies

Stay ahead of client filing deadlines

Add your clients below — or skip for now and add them from your account dashboard. PenaltyProof checks Companies House every morning and emails you before upcoming deadlines.

We only need company numbers and public Companies House data for deadline monitoring — no accounting software access, HMRC data, or client financial records.

No credit card 2-minute setup Official Companies House data

Work email

Filing alerts land here. Privacy Policy.

Drop your client list here

CSV, TXT, or Excel export — one company number per line, or comma-separated

Download sample CSV

Search by company name

Select from results to add the company number automatically.

Or type a company number directly

Press Enter or Space to add. Click × to remove.

Optional: Add companies now or later from your dashboard. Start with overdue clients or companies due in the next 30 days — the live preview puts urgent clients first.

Yes, send me filing tips and product updates. Things like end-of-quarter reminders, penalty traps, and new features. Optional — one-click unsubscribe in every email.

By clicking Start monitoring, you agree to our Terms of Service and Privacy Notice.

What happens next

1. Confirm your email — one click, arrives within seconds.

2. We check Companies House overnight for every client you've added.

3. PenaltyProof checks every morning — you get an alert if anything's due, nothing if the books are clear.

Example alert email

Example PenaltyProof filing deadline alert email

Open full sample alert

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