Filing Annual Accounts at Companies House: Complete Guide
Every UK limited company must file annual accounts at Companies House. This is separate from your CT600 corporation tax return (filed with HMRC), though the two are closely related.
This guide covers everything you need to know about Companies House annual accounts.
Two Filings, Two Deadlines
| Filing | To | Deadline |
|---|---|---|
| Annual accounts | Companies House | 9 months after year end |
| CT600 tax return | HMRC | 12 months after year end |
| Corporation tax payment | HMRC | 9 months + 1 day after year end |
For a year ending 31 March 2025:
- CH accounts due: 31 December 2025
- Tax payment due: 1 January 2026
- CT600 due: 31 March 2026
The Companies House deadline is the earliest. Many directors miss it because they focus on the HMRC deadline.
First Year Exception
In your first year, you get 21 months from incorporation to file accounts. After that, it's always 9 months.
What Goes in Your Accounts?
Your annual accounts must include:
- Balance sheet — what the company owns and owes at the year end
- Profit and loss account (unless dormant/micro-entity exemption)
- Notes to the accounts — accounting policies, additional details
- Director's report (unless small company exemption)
The level of detail depends on your company size.
Company Size Categories
The size thresholds changed for financial years beginning on or after 6 April 2025 (The Companies (Accounts and Reports) (Amendment and Transitional Provision) Regulations 2024). Check which regime applies to your accounting period.
Micro-Entity (simplest)
At least 2 of:
- Turnover ≤ £1 million (was £632,000 for financial years beginning before 6 April 2025)
- Balance sheet total ≤ £500,000 (was £316,000)
- ≤ 10 employees
What you file: Simplified balance sheet only. No profit and loss account. No director's report. Minimal notes.
Small Company
At least 2 of:
- Turnover ≤ £15 million (was £10.2 million for financial years beginning before 6 April 2025)
- Balance sheet total ≤ £7.5 million (was £5.1 million)
- ≤ 50 employees
What you file: Small companies can prepare abridged accounts (a condensed balance sheet and profit and loss account, with all members' consent) and can file "filleted" accounts — leaving out the profit and loss account and directors' report from the public record. (The old "abbreviated accounts" regime was abolished for periods beginning on or after 1 January 2016.) No audit required if you qualify for the small company audit exemption.
Medium and Large Companies
Full accounts with audit. Most companies reading this guide won't fall into these categories.
Filing Format: iXBRL
iXBRL (inline eXtensible Business Reporting Language) is a format where your accounts are both human-readable (HTML) and machine-readable (XBRL tags):
- Each number is "tagged" with a standardised code from an accounting taxonomy
- Systems can automatically process and validate the data
Where iXBRL is actually required differs between the two bodies:
- HMRC: iXBRL accounts have been mandatory since April 2011 for accounts attached to your CT600 company tax return.
- Companies House: electronic filing is currently optional — you can still use WebFiling or even paper. However, under the Economic Crime and Corporate Transparency Act (ECCTA), Companies House is moving to software-only filing from 1 April 2027: all accounts will have to be filed through commercial software, and the WebFiling and paper routes for accounts will close. From the same date, small and micro-entity companies will also have to file their profit and loss account.
Taxonomy Standards
- FRS 102 Section 1A — for small companies (most common)
- FRS 105 — for micro-entities (simplest)
- Full FRS 102 — for medium/large companies
Your filing software handles the iXBRL formatting automatically.
How to File
Option 1: Companies House WebFiling (Free)
Log into Companies House WebFiling and use their online forms. Suitable for micro-entities and dormant companies with very simple accounts. Note that this route is due to close when software-only filing becomes mandatory on 1 April 2027.
Option 2: Commercial Filing Software
Accounts production software can generate iXBRL-compliant accounts and submit them directly to Companies House through its software filing service. Better for companies with more complex accounts, and this becomes the only route from 1 April 2027.
Option 3: Accountant
Your accountant prepares and files accounts on your behalf. The most expensive option but provides professional assurance.
Late Filing Penalties
Companies House penalties are automatic and non-negotiable:
| How Late | Private Company | Public Company |
|---|---|---|
| Up to 1 month | £150 | £750 |
| 1–3 months | £375 | £1,500 |
| 3–6 months | £750 | £3,000 |
| Over 6 months | £1,500 | £7,500 |
Doubled if you file late two years in a row.
There is no appeal against these penalties unless there are exceptional circumstances (serious illness, natural disaster). "I forgot" or "my accountant was late" does not qualify.
These are separate from HMRC's late filing penalties for the CT600 (£100 initially, rising the later you file — doubled to £200 for filing dates on or after 1 April 2026).
Dormant Companies
If your company is dormant (no significant accounting transactions), you can file dormant company accounts. These are very simple — essentially just a balance sheet showing the company has no assets or liabilities beyond the initial share capital.
Dormant accounts can be filed through Companies House WebFiling for free.
Linking Accounts to Your CT600
When you file your CT600 with HMRC, you must include iXBRL accounts as an attachment. These should be consistent with (but not necessarily identical to) the accounts you file at Companies House.
Key differences:
- Companies House: small companies can file abridged or filleted accounts (less detail on the public record)
- HMRC: receives full accounts (including profit and loss) for tax purposes
The underlying data should be the same — only the level of disclosure differs.
Common Mistakes
1. Filing Accounts Late at CH but On Time at HMRC
The CH deadline (9 months) is 3 months earlier than HMRC (12 months). Don't confuse them.
2. Inconsistent Figures
If your CH accounts show different numbers from your CT600, expect questions from both bodies.
3. Wrong Accounting Standards
Using FRS 102 when you qualify for FRS 105 (or vice versa) can cause rejection. Check your company size category.
4. Missing Balance Sheet Signature
The balance sheet must be approved by a director. Electronic filing requires the director's name (not a physical signature).
Key Takeaways
- File accounts at CH within 9 months of your year end
- Choose the right size category — micro-entity is simplest for small companies, and thresholds rose for financial years beginning on or after 6 April 2025
- iXBRL is already mandatory for HMRC — and Companies House moves to software-only filing from 1 April 2027
- Penalties are automatic and there's effectively no appeal
- Keep figures consistent between CH accounts and HMRC CT600
Sort the HMRC Side with Taxpipe
Companies House accounts are one half of your annual obligations — the other half is your CT600 to HMRC. Taxpipe files your CT600 electronically through your own Government Gateway account, generating the iXBRL micro-entity or dormant accounts and tax computations HMRC requires.
File your CT600 now → — £59, with iXBRL accounts included for HMRC.