iXBRL (Inline eXtensible Business Reporting Language) is a digital format that embeds machine-readable tags within accounts so the figures can be read by both people and software. From April 2028, all UK companies must file their accounts with Companies House in iXBRL format using commercial software, as web and paper-based accounts filing will be withdrawn. Many businesses will already be familiar with iXBRL, as HMRC has long required it for accounts submitted with Company Tax Returns. The change brings Companies House into line with that approach and supports the transparency objectives of the Economic Crime and Corporate Transparency Act 2023 (ECCTA).

The new requirements apply to all UK registered companies, regardless of size – including small companies, micro-entities and dormant companies. There are no exemptions based on turnover, sector or company structure: if your company files accounts at Companies House, the rules apply. The changes affect any accounts filing made in or after April 2028, whatever accounting period it relates to. Limited liability partnerships and groups with multiple UK entities should also review how each entity files, as every set of accounts submitted to the registrar will need to meet the new software-only requirement.

The changes apply to any Companies House filing made from April 2028 onwards, giving companies around 21 months to prepare. Sensible first steps include confirming how your accounts are currently filed, checking whether your accounts preparation software supports iXBRL filing to Companies House, and speaking to your accountant about whether anything needs to change. Companies that still file on paper or through the Companies House web service for accounts will need to move to commercial software or appoint an agent, such as an accountancy firm, to file on their behalf before the deadline.

No. The option to file abridged accounts will be removed for filings made from April 2028. Small companies and micro-entities will instead need to file their full statutory accounts, including a profit and loss account, with Companies House. This is one of the most significant changes for smaller businesses, as abridged accounts have allowed many to limit the financial detail placed on the public register. Directors of small companies should consider now how this affects what they disclose, and whether their year-end and filing processes need to adapt.

No – these reforms relate only to filings made with Companies House. Your obligations to HMRC, including filing a Company Tax Return with iXBRL-tagged accounts and paying corporation tax, are a separate compliance regime and continue unchanged. The two are often confused because both involve submitting company accounts, but they are made to different bodies under different legislation and on different deadlines. The practical effect of the 2028 changes is that the format Companies House requires will more closely mirror what HMRC already expects, which may simplify processes for companies using joined-up filing software.

Accounts submitted by post or through the closed web service after the changes take effect will not be accepted, and a rejected filing does not stop the clock on your statutory deadline. Companies that fail to file acceptable accounts on time face automatic late filing penalties, which escalate the longer accounts remain outstanding, and persistent non-compliance can lead to prosecution of directors or the company being struck off the register. The safest approach is to confirm well before April 2028 that you, or your accountant, can file in iXBRL format using commercial software.

Companies will need access to commercial software capable of filing iXBRL accounts with Companies House – but that does not necessarily mean buying it themselves. Many businesses will already be covered because their accountant files electronically on their behalf using compliant software; BKL clients who submit accounts through us electronically will be largely unaffected. Companies that currently self-file via the web service or on paper will need to either adopt suitable software or engage an agent to file for them. The right answer depends on company size, in-house finance resource and how the rest of your compliance is managed.

Yes, but less freely than before. As part of the ECCTA reforms, the number of times a company can shorten its accounting reference period will be reduced from April 2028. Changing an accounting reference date is sometimes used to align year-ends across a group, manage filing deadlines or support a transaction, so businesses planning a restructure, sale or group reorganisation should factor the new restriction into their timetable. If a change of year-end is on the horizon, it is worth taking advice early so it can be carried out under the current, more flexible rules where appropriate.

BKL’s accounting, company secretarial and corporate governance specialists can review how your accounts are currently prepared and filed, confirm whether you are affected, and manage the transition to software-only iXBRL filing on your behalf. Clients who already file electronically through BKL are effectively compliant with the new format requirements, and we will advise on any additional steps – such as the profit and loss opt-out for small companies – well before April 2028. If you would like to discuss what the changes mean for your company or group, get in touch with our team.