How to File Annual Accounts With Companies House

When your accounts are due

Companies House sets two different deadlines depending on whether you are filing for the first time. Your very first accounts are due 21 months after the date you registered with Companies House. This longer window recognises that a new company's first accounting period is often more than twelve months.

After that first filing, your annual accounts are due 9 months after the end of your company's financial year. That financial year end is fixed by your accounting reference date. It is a hard deadline: Companies House issues a penalty automatically if accounts arrive late, and it does not send a reminder invoice first.

Keep the Companies House deadline separate in your mind from your obligations to HM Revenue and Customs. You must pay Corporation Tax, or tell HMRC that your company owes none, by 9 months and 1 day after your accounting period ends, and file your Company Tax Return within 12 months of the accounting period ending. The accounts filed at Companies House and the accounts submitted to HMRC come from the same figures but are separate submissions.

Work out your company size

The accounts you must prepare and file depend on which size bracket your company falls into. A company qualifies for a size category by meeting at least two of the three conditions for that category: turnover, balance sheet total and average number of employees. These thresholds increased for accounting periods beginning on or after 6 April 2025, so check you are using the current figures.

A micro-entity is the smallest bracket and gets the most generous simplifications. Small companies can also use lighter-touch accounts and audit exemptions. Medium-sized companies must deliver all the component parts of their accounts to Companies House. Anything above the medium thresholds is treated as a large company and files full statutory accounts.

Getting your size classification right matters because it drives everything else: what you prepare, what the public register shows and whether you need an audit. If you are close to a threshold, review your position each year, because two consecutive years above a limit will usually move you into the larger bracket.

Which accounts each company type files

Micro-entities may prepare simpler accounts that meet the statutory minimum and can send only a balance sheet, with less information, to Companies House. They receive the same exemptions available to small companies. Small companies can currently omit the profit and loss account and the directors' report when they file with Companies House, and many qualify for audit exemption.

It is important to separate the accounts that go on the public register from the full statutory accounts. Even where you can file a lighter version at Companies House, the full statutory accounts must still go to your members and to HMRC as part of your tax obligations. The board of directors must approve the accounts before they are sent to members and filed.

Medium-sized and large companies get fewer simplifications. A medium-sized company must deliver all the component parts of its accounts to Companies House, and large companies file full statutory accounts with an audit. Whatever your size, the underlying figures must be prepared to the same accounting standards; the size rules only affect how much you disclose and file.

How to file your accounts

For most small and micro-entity companies, the practical route today is online filing through Companies House. To use the online service you need your company's Companies House password and authentication code, which you can register for if you do not already have them. Before you file anything, your company directors must approve the accounts.

Increasingly, companies and their accountants file using commercial accounting software that connects directly to Companies House. This route tags the figures in the accounts so they can be read automatically, and it will become the only route from April 2028. If you use an accountant, they will usually file on your behalf through their software.

Whichever method you use, file well before the deadline rather than on the day. Filing is not instant if the submission is rejected for an error, and you remain responsible for the deadline even if a rejected filing has to be corrected and resubmitted. Building a buffer of a week or two protects you from an automatic penalty caused by a last-minute problem.

Late filing penalties

If your accounts arrive after the deadline, Companies House issues a penalty automatically. The amount depends on how late a private company files. The bands run from £150 for accounts up to one month late, rising to £1,500 for accounts more than six months late.

There is a further sting for repeat lateness: the penalty is doubled if your accounts are filed late two years in a row. So a private company that is more than six months late for a second consecutive year faces a penalty of £3,000. Penalties for public limited companies are set at different, higher levels.

The penalties are for late filing alone and are separate from any consequences of not filing at all, which can ultimately lead to the company being struck off and directors facing prosecution. Treat the deadline as immovable and file early to avoid these costs entirely.

The changes coming in April 2028

The Economic Crime and Corporate Transparency Act 2023 introduced a package of reforms to how accounts are filed, and the government has confirmed these take effect from 1 April 2028. The headline change is that software-only filing becomes mandatory: from that date the Companies House web and paper filing systems will be closed for accounts, and all companies and LLPs must file using commercial software in inline eXtensible Business Reporting Language (iXBRL) format.

For smaller companies the bigger practical change is disclosure. Small companies and micro-entities will have to file a profit and loss account with Companies House, as other companies already do. To address privacy and commercial concerns, they will be able to opt out of publishing that profit and loss information on the public register. The reforms also introduce a strengthened eligibility statement for any company claiming an audit exemption.

Companies House has framed the timeline as giving businesses one full accounting year plus nine months, in effect 21 months, to prepare before the April 2028 deadline. If you file yourself using the web service today, the sensible step is to plan your move to compatible software, or to an accountant who files through software, well ahead of the switch. Building the right controls into your reporting cycle now, using a platform such as Nasara Connect's compliance tooling, makes that transition far smoother.

Conclusion

Filing annual accounts with Companies House comes down to three things: knowing your deadline, filing the right accounts for your company size and submitting on time through an accepted method. Your first accounts are due 21 months after registration and every set after that is due 9 months after your financial year end. The penalties for missing those dates are automatic and rise the longer you leave it, doubling for a second consecutive late year.

The reforms taking effect from 1 April 2028 will end web and paper filing and require software-based iXBRL submissions, while small and micro-entity companies will begin filing a profit and loss account with an option to keep it off the public register. Preparing early is the safest approach. If you are setting up a company and want the filing calendar and controls handled from day one, explore how Nasara Connect supports company formation so your first accounts, and every set after, are filed correctly and on time.

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