About DormantFile
Why DormantFile exists
Our founder built DormantFile out of necessity. He runs several dormant limited companies in the UK — holding structures, side projects that never launched, companies kept open for future plans. Every year, each one needs the same two filings:
- Annual accounts to Companies House
- A nil CT600 Corporation Tax return to HMRC
The companies do nothing, but the paperwork never stops.
For years, the free HMRC tool (CATO) handled the tax return side. It wasn't pretty, but it worked and it cost nothing. When HMRC announced CATO was closing — it closed on 31 March 2026 — the alternatives were bleak: hire an accountant at £80–£150 per company per year for a zero-activity filing, or buy general-purpose accounting software that's overkill for a company with no transactions.
Neither option made sense. So we built DormantFile.
What DormantFile does
DormantFile handles both filings that a dormant UK limited company needs each year:
- Annual accounts — prepared and submitted directly to Companies House via their official software filing API.
- Nil CT600 Corporation Tax return — prepared and submitted directly to HMRC via their GovTalk API.
Both filings confirm that your company was dormant during the accounting period. No transactions, no tax liability. DormantFile handles the XML, the submission, and the confirmation — you just review and click submit.
We also send email reminders at 90, 30, 14, 7, 3, and 1 days before each deadline, so you never miss a filing date.
Who we are
DormantFile is built and run by a solo founder based in the UK. He's a software engineer, not an accountant. DormantFile is software — it prepares and submits your filings, but it does not provide accounting or tax advice. If your company has traded, or you're unsure whether it qualifies as dormant, you should speak to a qualified accountant.
We focus exclusively on dormant companies. If your company has any trading activity, DormantFile is not the right tool for you.
Our approach
- Affordable — from £19/year, because filing a nil return shouldn't cost more than the company earns (which is nothing). See our pricing for details.
- Secure — your HMRC credentials are used once to submit your filing and then discarded. We never store them. Your Companies House authentication code is handled the same way. Read our security page for the full details.
- Simple — no features you don't need. No invoicing, no payroll, no VAT. Just the two filings a dormant company actually requires. See how it works for a walkthrough.