You file annual accounts with Companies House through WebFiling, the joint Companies House/HMRC filing service, or accounting software that submits iXBRL on your behalf. The deadline is nine months from your accounting reference date for a private limited company, with first accounts due 21 months from incorporation. Late filing triggers automatic penalties from £150 to £1,500.
This guide covers your filing options, the format choices, the step-by-step submission process, common rejection reasons, and what to do if you cannot meet the deadline.
Choose your filing method
Three main routes for filing accounts:
WebFiling
Companies House WebFiling is the free direct service. You log in with your authentication code and key in figures into the form. Suitable for small and micro-entity accounts, particularly dormant accounts and simple filleted accounts. Larger or more complex accounts are awkward to enter manually.
Joint filing service
The joint filing service lets you submit your accounts to Companies House and your Corporation Tax return to HMRC at the same time. Designed for small companies with straightforward accounts. The service generates a single iXBRL package for both filings.
Accounting software
Most accountants and growing businesses file through cloud accounting software (Xero, QuickBooks Online, FreeAgent, Sage Business Cloud, IRIS, BTC) that connects to Companies House and HMRC via API. The software prepares iXBRL-tagged accounts and submits them in one click. This is the standard route for almost all professionally-prepared accounts.
Paper
Paper filing remains permitted for some accounts but is slower, more expensive, and more error-prone. First accounts cannot be filed on paper if they include audited results or if the company size requires iXBRL.
To pick a platform that handles iXBRL filing for you, compare cloud accounting software with built-in Companies House filing.
What format to file
Small companies have four format choices:
- Full accounts. Directors’ report, profit and loss, balance sheet, notes, and (where required) auditor’s report. Filed in full or filleted.
- Abridged accounts. Shorter form with shareholder consent, profit and loss starting at gross profit. Filed in full or filleted.
- Micro-entity accounts. Simplified format under FRS 105 for the smallest companies (turnover ≤ £1m, balance sheet ≤ £500k, ≤ 10 employees, any two of three).
- Filleted accounts. Full or abridged accounts with the profit and loss account and certain notes omitted from the public Companies House filing only.
Larger companies (medium and large) must file full accounts with no abridgement option. Audit may also apply.
For more on choosing between abridged, micro-entity, and filleted, see our guide on abbreviated vs full accounts.
Step-by-step filing process
The standard sequence:
- Confirm your accounting reference date and period. Your ARD is the last day of your financial year. The accounting period you are filing covers the year ending on that ARD.
- Prepare accounts. Under FRS 102 (Section 1A for small companies) or FRS 105 (micro-entities). Get all figures finalised, the directors’ report (if applicable) drafted, and the balance sheet ready for signature.
- Director signs the balance sheet. Companies Act 2006 section 414 requires the balance sheet to be signed by a director. The signature can be electronic in most software.
- Tag iXBRL. All online accounts filings require iXBRL tagging — extensible business reporting language that lets HMRC and Companies House parse the figures. Accounting software handles this automatically. Manual iXBRL preparation is rarely worthwhile.
- Submit. Through your software, the joint service, or WebFiling. You will receive a submission reference immediately.
- Confirm acceptance. Companies House emails an acceptance confirmation, typically within minutes for most filings, longer for complex accounts. If accounts are rejected, the email gives the reason.
Keep the acceptance email and a PDF of the filed accounts in your records.
First accounts: special rule
The deadline for first accounts after incorporation is 21 months from the incorporation date, not nine months from the ARD. The first accounting period is typically longer than 12 months because it runs from incorporation to your ARD.
For example, a company incorporated on 14 March 2024 with a 31 March ARD has a first accounting period from 14 March 2024 to 31 March 2025. First accounts are due by 14 December 2025 (21 months from incorporation), not by 31 December 2025 (nine months from ARD).
Subsequent periods are 12 months and the standard nine-month rule applies.
Common rejection reasons
Five reasons cover most rejections:
- Wrong accounting period. Dates that do not match your ARD or that overlap with the previous period filed.
- Missing director signature. The balance sheet must be signed (or e-signed). A draft submitted without signature will be rejected.
- iXBRL corruption. Tags inconsistent with figures or schema validation errors. Almost always caused by manual interference with software-generated XBRL.
- Format too small to read. PDF-based paper submissions sometimes fail readability checks, particularly when scaled down to fit page margins.
- Wrong format for company size. Filing micro-entity accounts when the company has crossed thresholds, or filing abridged accounts without recording shareholder consent.
If your accounts are rejected, you typically have to fix the issue and resubmit. The original submission date does not protect you against late filing penalties if the resubmission lands after the deadline.
Late filing penalties
Penalties for late accounts at Companies House for a private company:
| How late | Penalty |
|---|---|
| Up to 1 month | £150 |
| 1–3 months | £375 |
| 3–6 months | £750 |
| Over 6 months | £1,500 |
Penalties double automatically if accounts are filed late in two consecutive years. PLC penalties are higher.
Penalties are issued by Companies House and are recoverable as a civil debt. Appeals are limited to genuine technical issues (such as a Companies House system failure that prevented timely filing). Routine reasons (busy, accountant absent) are not accepted.
How to extend a deadline
In exceptional circumstances, you can apply for a deadline extension before the existing deadline expires. Extensions are granted at Companies House’s discretion only where there is a genuine unforeseen event outside your control. Applications are made via the Extend Your Filing Deadline service on GOV.UK.
Routine reasons are not accepted. Plan to file at least four to six weeks ahead of deadline so a rejection or technical issue does not push you past the cliff.
Key takeaways
- Three main filing routes: WebFiling, joint Companies House/HMRC service, accounting software (most common)
- Deadlines: 9 months from ARD for private Ltd, 21 months from incorporation for first accounts
- All online accounts require iXBRL tagging, handled automatically by accounting software
- Common rejections: wrong period, missing signature, iXBRL corruption
- Penalties scale from £150 to £1,500, doubled for two consecutive late years
- Extensions are granted only for exceptional, unforeseen circumstances
Frequently asked questions
Can I file accounts online myself? Yes. Companies House WebFiling is free. For small and dormant companies, manual entry works. For more complex accounts, accounting software is faster and less error-prone.
Do I need iXBRL? Yes for all online accounts filings. Accounting software handles iXBRL tagging automatically. Manual iXBRL is rarely the right approach.
What is the deadline for my first accounts? 21 months from your incorporation date, not nine months from your ARD. Subsequent accounts return to the standard nine-month rule.
What happens if my accounts are rejected? You fix the issue and resubmit. The submission deadline is calculated against the date you successfully filed accepted accounts, not the rejected attempt — so plan to file well ahead of deadline to handle rejections.
Can I extend my Companies House filing deadline? Only in exceptional circumstances, applied for before the existing deadline expires. Routine reasons such as a busy schedule are not accepted.
Useful resources
Companies House — File your company accounts https://www.gov.uk/file-your-company-annual-accounts
GOV.UK — Late filing penalties https://www.gov.uk/government/publications/late-filing-penalties
Companies House — Extend your filing deadline https://find-and-update.company-information.service.gov.uk/extensions