If you run a small UK company, a change is coming that will eventually affect every single one of the 5.5 million-plus companies on the Companies House register: from 1 April 2028, you will no longer be able to file your annual accounts on paper or through the free Companies House web filing service. Every company will have to file using commercial software.
This page explains what's actually changing, who it affects, and what "commercial software" means in practice, in plain English, without assuming you already have an accountant.
The short version: from 1 April 2028, annual accounts must be filed with Companies House using software that produces the iXBRL data format, not the free web form or a paper form. This applies to dormant companies and micro-entities too, not just larger trading companies.
What's actually changing
Companies House currently lets most small and micro-entity companies file simple accounts through a free online form, or by post. That closes. From 1 April 2028, Companies House has confirmed that web and paper accounts filing routes are expected to close, and annual accounts move to software-only filing in the iXBRL format: the same tagged-data format HMRC already requires for Corporation Tax returns.
This is part of a wider shift under the Economic Crime and Corporate Transparency Act (ECCTA), which is also introducing identity verification for directors and people with significant control, and greater scrutiny of company filings generally.
Why it's happening
Companies House wants filings it can check programmatically rather than read as free text or a scanned PDF. iXBRL tags each figure in a set of accounts (turnover, profit, assets, and so on) so it can be validated automatically. That's harder to fake and cheaper for Companies House to process at scale, and 5.5 million-plus companies is a lot of paper.
Who's affected
Everyone with a UK company. That includes:
- Dormant companies that have never traded but still file accounts every year to stay on the register.
- Micro-entity companies, the smallest category, which currently qualify for the simplest accounts and often use the free web service.
- Small and medium trading companies, who in many cases already use accounting software or an accountant, but whose software will need to support the new filing route.
If you currently type your figures into the Companies House website once a year and click submit, that specific route is the one closing.
What "commercial software" means
It doesn't mean you need an in-house accounts team or enterprise finance software. It means software from any provider, ranging from full accountancy platforms to small, focused tools built for exactly this filing, that can produce a set of accounts in the iXBRL format and submit it through the correct Companies House filing route. For a dormant or micro-entity company, that can be a genuinely simple, five-minute job once the right software exists; it's the format and submission method that's changing, not necessarily the complexity of your actual accounts.
What to do now
- Check which category your company falls into: dormant, micro-entity, small, or larger, since that affects exactly what your accounts need to contain.
- Don't wait until March 2028. The web filing service is expected to close as the deadline approaches, and every company will eventually need a software route regardless of company size.
- If you already use an accountant, ask whether their existing software already supports iXBRL accounts filing under the new rules. Many will, since Corporation Tax filing has required iXBRL for years.
- If you file it yourself for a dormant or micro-entity company, look for software built specifically for that case rather than a full accountancy suite. That's a narrower, cheaper problem to solve than general bookkeeping software.
Digital Filing Systems is building CompanySimple: accounts, CT600, confirmation statement and deadline monitoring for dormant and small companies, as part of this shift. It's on our roadmap; see the current status of every product we're building.