Free plan — up to 5 companies

Stay ahead of client filing deadlines

Add your clients below — by company number, name search, or bulk CSV import. 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.

Tip: Start with overdue clients or companies due in the next 30 days. When Companies House data is available, the live preview will put those 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. You get an alert at 07:00 GMT/BST — or an all-clear if nothing's due soon.

Example alert email

Example PenaltyProof filing deadline alert email

Open full sample alert

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