Software only accounts filing at Companies House

Q: How does the deadline work around 1 April 2028?

Illustration only. A private company has a year end of 30 June 2027. Under sections 442 and 443 its accounts are due at Companies House by 31 March 2028, the last day before web and paper filing closes for accounts. If the directors file on the web service on 25 March 2028 and the accounts are accepted, they are on time. If those accounts are rejected on 30 March for a missing statement and the corrected version is not ready until 3 April, it can only be filed through software. A rejected document counts as never delivered, so the accounts are late and attract a penalty, which for a private company is £150 if delivered not more than one month late. If an error is found in June 2028 and the directors need to file revised accounts, those must also be filed through software. The lesson is that a company relying on web filing should not plan to file in the final days of March 2028. Companies House late filing guidance says delivery means actual receipt at Companies House in the correct format, and the penalty is automatic. See accounts deadlines and penalties and why Companies House rejects filings.

Q: What mistakes should small companies avoid?

Assuming any bookkeeping package will file. Check specifically that it produces iXBRL accounts and can submit them to Companies House for the type of accounts the company prepares, whether micro entity, small, dormant or full. Leaving the presenter account until the last week. It is a separate application from the software subscription. Forgetting revised and late accounts. Anything filed on or after 1 April 2028 must go through software, whatever period it covers. Not reviewing the tags. Automatic tagging still needs a human check, and it is better to run a trial set of accounts through the software well before the deadline. Thinking an accountant removes the responsibility. Companies House guidance says that even when a professional files, the company remains legally responsible for its accounts. Treating it as a Companies House only change. If the company used HMRC's closed joint service, it needs software for the tax return now, not in 2028. Company directors can protect the business against the cost of an HMRC check with tax investigation insurance, which pays up to £100,000 of accountant's fees with Solar Protect. Read how our cover works or get a quote.

From 1 April 2028 every company must file its annual accounts with Companies House through commercial software, in inline XBRL (iXBRL) format. The Companies House web filing service and paper filing close for accounts on that date with no transition period, so any small company that still uses the free online service or posts paper accounts needs suitable software, or an agent who has it, in place before then.

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What exactly is changing in April 2028?

Companies House guidance says that from 1 April 2028 all companies must file their accounts using commercial software. This applies whether directors file the accounts themselves or use an accountant or other agent. From the same date the web and paper services close for accounts, and Companies House says there will be no transition period. Its guidance also makes clear that revised accounts are caught: a set of amended accounts filed after the cut over must go through software too.

The change only affects accounts. Companies House has confirmed that its web filing services will remain available for other filings, including confirmation statements and changes to director details. A company that files its confirmation statement online today can carry on doing so.

Software filing is one of a package of accounts reforms announced on 9 June 2026, which were moved from April 2027 to April 2028 to give companies 21 months to prepare. The other reforms, including the end of abridged accounts and the requirement for small and micro entity companies to file a profit and loss account, are covered in small company accounts filing options. This page deals with the mechanics of moving to software.

Where does the legal power to require software filing come from?

Section 1068 of the Companies Act 2006 allows the registrar to set requirements for the form, authentication and manner of delivery of documents. Section 1068(4) covers the physical form of a document (hard copy or electronic), the means of delivery, and, for electronic delivery, the hardware, software and technical specifications to be used. Section 1068(4A), inserted by section 75 of the Economic Crime and Corporate Transparency Act 2023, requires those delivery requirements to be imposed by registrar’s rules.

The same 2023 Act omitted section 1069, the old power to require electronic delivery, and subsections (5) to (6A) of section 1068. The government’s factsheet on the registrar’s powers describes this as removing constraints on the registrar’s powers to make rules which mandate digital delivery. It also added section 1068A, which lets registrar’s rules require documents to be delivered together. That is the basis for the separate reform requiring all the component parts of filed accounts and reports to be filed together.

The practical point is that once the rules require software, accounts sent any other way do not meet the requirements for proper delivery in section 1072. Under section 1072(2) a document that is not properly delivered is treated as not having been delivered at all.

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What is iXBRL and why does it need software?

Companies House receives software filed accounts in inline extensible business reporting language. Its guidance describes this as a worldwide technical standard that combines HTML with machine readable tags, so the same document can be read by people and by computers. Each figure in the accounts, such as turnover, net assets or the number of employees, carries a tag identifying what it is.

Companies House says not all software supports the iXBRL tagging needed to file digital accounts, so having accounts software is not the same as having software that can file with Companies House. Where software applies tags automatically, someone still needs to check them. A tag on the wrong line is not a cosmetic error, because Companies House gives as one reason for the change the chance to aggregate, compare and analyse accounts data more widely.

What does a company need before it can file through software?

The Companies House guidance lists three things:

the company’s authentication code;
a presenter account, which gives a presenter ID and code; and
a Companies House credit account, but only if the company will be filing documents that carry a fee.

Software sends filings to Companies House through its XML gateway. The benefits Companies House lists include immediate acknowledgement of receipt and automatic confirmation when a filing is accepted or rejected. GOV.UK has a search tool to find software suitable for the type of accounts being filed, and Companies House states that it does not endorse or recommend particular products.

If the company already uses software for something else, such as payroll, the guidance suggests checking whether it can add Companies House accounts filing. Some products also file with HMRC at the same time.

How does this fit with filing accounts at HMRC?

HMRC has already made a similar move. Its joint online service for filing accounts and the Company Tax Return closed on 31 March 2026. From 1 April 2026 HMRC says companies should use commercial software to file accounts and Company Tax Returns with it, and a paper Company Tax Return is only possible with a reasonable excuse or when filing in Welsh. HMRC’s guidance reminds companies that annual accounts must still be filed with Companies House separately.

Many small companies that used the joint HMRC service will already have bought software for the tax return. The question to ask the provider is whether that product also files accounts with Companies House in iXBRL. Companies House notes that deadlines can differ: the Company Tax Return is due 12 months after the end of the accounting period, while a private company’s accounts are normally due at Companies House nine months after the end of its accounting reference period under section 442. See Corporation Tax deadlines for the HMRC side.

What about package accounts, CICs and overseas companies?

Some submissions contain more than one component, such as several sets of accounts or accounts plus a Companies House form. Companies House calls these package accounts. They must be iXBRL tagged using software and saved as a ZIP file, then uploaded through the package accounts service. Companies House lists the types that can be filed this way, including community interest companies, audit exempt subsidiary and dormant exempt subsidiary accounts, limited partnerships, UKSEF accounts for listed companies, group packages under sections 400 and 401, and Welsh accounts with an English translation.

Companies House says the package service will still be available after 1 April 2028, but the ZIP file must be produced by software. A ZIP file of untagged documents put together by hand will not meet that requirement.

How does the deadline work around 1 April 2028?

Illustration only. A private company has a year end of 30 June 2027. Under sections 442 and 443 its accounts are due at Companies House by 31 March 2028, the last day before web and paper filing closes for accounts.

If the directors file on the web service on 25 March 2028 and the accounts are accepted, they are on time.
If those accounts are rejected on 30 March for a missing statement and the corrected version is not ready until 3 April, it can only be filed through software. A rejected document counts as never delivered, so the accounts are late and attract a penalty, which for a private company is £150 if delivered not more than one month late.
If an error is found in June 2028 and the directors need to file revised accounts, those must also be filed through software.

The lesson is that a company relying on web filing should not plan to file in the final days of March 2028. Companies House late filing guidance says delivery means actual receipt at Companies House in the correct format, and the penalty is automatic. See accounts deadlines and penalties and why Companies House rejects filings.

What mistakes should small companies avoid?

Assuming any bookkeeping package will file. Check specifically that it produces iXBRL accounts and can submit them to Companies House for the type of accounts the company prepares, whether micro entity, small, dormant or full.
Leaving the presenter account until the last week. It is a separate application from the software subscription.
Forgetting revised and late accounts. Anything filed on or after 1 April 2028 must go through software, whatever period it covers.
Not reviewing the tags. Automatic tagging still needs a human check, and it is better to run a trial set of accounts through the software well before the deadline.
Thinking an accountant removes the responsibility. Companies House guidance says that even when a professional files, the company remains legally responsible for its accounts.
Treating it as a Companies House only change. If the company used HMRC’s closed joint service, it needs software for the tax return now, not in 2028.

Company directors can protect the business against the cost of an HMRC check with tax investigation insurance, which pays up to £100,000 of accountant’s fees with Solar Protect. Read how our cover works or get a quote.

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Sources

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 8 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.