Filing your company accounts is not optional. Every limited company registered in the UK must file annual accounts with Companies House and deliver a corporation tax return to HMRC. Miss the deadlines and you face automatic penalties, a damaged credit profile, and in persistent cases the company being struck off.
Below is the whole process, in the order you actually do it: what to prepare, which accounts regime you fall into, where each filing goes, every deadline including the awkward first-year ones, and what changes when Companies House moves to software-only filing in April 2028. Whether you run a single-director consultancy in Shoreditch or a four-employee manufacturing firm in the Birmingham Jewellery Quarter, the mechanics are the same.
What Are Company Accounts?
Company accounts (also called annual accounts or statutory accounts) are a formal record of your company's financial performance and position for a financial year. They include:
- A profit and loss account (income statement)
- A balance sheet
- Notes to the accounts (explanatory notes)
- A directors' report (small companies are exempt; micro-entities do not prepare one)
The accounts must give a true and fair view of the company's affairs. They are prepared from your bookkeeping records under UK GAAP: FRS 102 (or its simpler Section 1A for small companies), or FRS 105 for micro-entities.
Who Needs to File Company Accounts?
Every private limited company registered at Companies House must file accounts each year, including single-director companies, dormant companies, and companies that made a loss or never traded. Sole traders and partnerships do not file company accounts; they report through self assessment (SA100 with self-employment pages, or the SA800 partnership return). If you have recently incorporated, the rules apply from day one.
Micro-Entity, Small or Full: Which Accounts Regime Are You In?
Your company size decides how much you must prepare and how much appears on the public register. The thresholds below apply for financial years beginning on or after 6 April 2025 (they were uplifted by around 50%; the old small-company turnover ceiling was £10.2 million). You qualify for a regime by meeting any two of its three tests, per the Companies House guidance at gov.uk.
| Regime | Turnover | Balance sheet total | Average employees | What you can file at Companies House |
|---|---|---|---|---|
| Micro-entity | £1 million or less | £500,000 or less | 10 or fewer | Simplified FRS 105 accounts; balance sheet only, minimal notes |
| Small company | £15 million or less | £7.5 million or less | 50 or fewer | Filleted accounts (no profit and loss account or directors' report on the register); abridged accounts until April 2028 |
| Medium and large | Above small thresholds | Above small thresholds | More than 50 | Full accounts, with audit unless exempt |
Two practical points. First, whatever you file publicly, HMRC always receives the full accounts with your tax return; you cannot keep turnover from HMRC. Second, the privacy advantage is shrinking: under the Economic Crime and Corporate Transparency Act reforms, small companies and micro-entities will have to file a profit and loss account (with an option to keep it off the public register), and abridged accounts are being withdrawn (see the April 2028 section below).
Two Filing Destinations: Companies House and HMRC
This is the most common point of confusion. You do not file company accounts in one place. You file to two separate bodies:
- Companies House receives your annual accounts (the statutory accounts) for the public register.
- HMRC receives your company tax return (form CT600) with the full accounts attached.
Filing at one does not count as filing at the other, and the deadlines are different. Directors who file filleted accounts at Companies House sometimes assume the job is done; HMRC will still chase the CT600.
Every Filing Deadline in One Table
The deadlines are strict and there is no grace period for first-time filers. Per Companies House guidance, a private company's first accounts are due 21 months from incorporation (or 3 months from the accounting reference date, whichever is longer); after that it is 9 months from the year end.
| Filing | Goes to | Deadline |
|---|---|---|
| First annual accounts | Companies House | 21 months after incorporation |
| Annual accounts (every year after) | Companies House | 9 months after the accounting reference date (year end) |
| Corporation tax payment | HMRC | 9 months and 1 day after the end of the accounting period |
| Company tax return (CT600) | HMRC | 12 months after the end of the accounting period |
| Confirmation statement (CS01) | Companies House | Within 14 days of the end of each 12-month review period |
Note the odd ordering on the HMRC side: you must pay the corporation tax before the return that calculates it is due. In practice you prepare the accounts and the tax computation together, pay by 9 months and 1 day, and file the CT600 at the same time. Our guide to how much corporation tax you pay covers the 19% and 25% rates and marginal relief between £50,000 and £250,000 of profit.
Your accounting reference date is set automatically at incorporation (the last day of the month of your first anniversary). You can change it by filing form AA01, within limits. Most companies settle on 31 March, 30 April or 31 December for simplicity.
Worked Example: A New Company's First-Year Timeline
Say you incorporate a design company in Leeds on 10 June 2026.
- Accounting reference date: Companies House sets it to 30 June 2027, the last day of the month of your first anniversary. Your first accounts run 10 June 2026 to 30 June 2027, slightly longer than 12 months.
- First confirmation statement: the review period ends 9 June 2027; file by 23 June 2027 (14 days later).
- First accounts due at Companies House: 10 March 2028, which is 21 months after incorporation. Every later year the deadline is 30 March, 9 months after the 30 June year end.
- Corporation tax: because a corporation tax accounting period cannot exceed 12 months, your first accounts are split into two periods for HMRC: 10 June 2026 to 9 June 2027, then 10 June to 30 June 2027. Tax on the first period is payable by 10 March 2028 and on the stub period by 1 April 2028; the two CT600s are due 9 June 2028 and 30 June 2028.
Two CT600s for one set of accounts catches many first-time directors out. It also shows why the first year is the worst one to leave until the deadline: the Companies House and HMRC payment dates land within weeks of each other.
Step-by-Step: How to File Company Accounts in the UK
Step 1: Prepare Your Accounts from Your Bookkeeping Records
Before you file anything, the accounts must be prepared: raw bookkeeping data (sales invoices, purchase receipts, bank statements, payroll records) turned into a set of statutory accounts under the right standard for your size. Most small companies use software such as Xero, FreeAgent, QuickBooks or Sage, which can generate draft accounts. The final accounts still need to comply with UK GAAP, and the balance sheet must be approved by the board and signed by a director. Without that signature, Companies House rejects the filing.
Step 2: Decide Which Filing Format to Use at Companies House
Check the size table above. Micro-entities file simplified FRS 105 accounts. Small companies can currently choose full, abridged, or filleted accounts; most directors pick filleted accounts to keep the profit and loss account and directors' report off the public register, because competitors and customers can search Companies House for free. Remember the caveat: abridged accounts disappear in April 2028 and a profit and loss account will have to be filed (though not necessarily published).
Step 3: File Your Accounts with Companies House
You can currently file through the Companies House WebFiling service or through third-party software; most accountants use software that files directly (Xero, FreeAgent and IRIS all offer this). You need your company authentication code, the 6-character code issued at incorporation. If you have lost it, request a replacement through the Companies House online service; it arrives by post to the registered office, so allow a few days. The filing itself takes minutes once the accounts are ready, and the public register updates shortly after acceptance.
Step 4: File Your Corporation Tax Return with HMRC
The second filing. You submit form CT600 through HMRC's online service or accounting software. The CT600 includes:
- Company details and the accounting period
- Profit per the accounts, then tax adjustments (disallowable expenses, capital allowances)
- The corporation tax calculation
- Any reliefs or claims (capital allowances, R&D relief, group relief, loss claims)
You attach the full accounts, not the filleted version, in iXBRL format. If you claim R&D relief you must also submit the Additional Information Form or HMRC will remove the claim.
Step 5: Pay Your Corporation Tax
Payment is due 9 months and 1 day after the period end, referenced with your company's 10-digit UTR. Companies with taxable profits above £1.5 million (shared between associated companies) pay by quarterly instalments instead; most owner-managed companies pay in one amount. Paying early earns a small amount of credit interest from HMRC, which is worth knowing if the cash is sitting idle.
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Penalties for Late Filing
Companies House penalties are automatic; there is no warning letter. HMRC's penalties for a late CT600 are entirely separate and can apply at the same time.
| How late | Companies House (accounts, private company) | HMRC (CT600) |
|---|---|---|
| 1 day | £150 (up to 1 month band) | £100 |
| 1 to 3 months | £375 | A further £100 at 3 months |
| 3 to 6 months | £750 | At 6 months, 10% of the estimated unpaid tax |
| More than 6 months | £1,500 | A further 10% at 12 months |
The Companies House penalty doubles if your accounts are late two years in a row, and the bands are higher for public companies. HMRC's fixed penalties rise to £500 each if the return is late three accounting periods running, and interest runs on unpaid tax from the due date regardless. Late filing also flags on the public register, and banks, suppliers, credit insurers and potential buyers all check it. Missing the deadline even by one day costs money.
Software-Only Filing from 1 April 2028 (ECCTA)
Under the Economic Crime and Corporate Transparency Act 2023 reforms, Companies House has confirmed that all accounts filed on or after 1 April 2028 must be filed by commercial software in iXBRL format. From that date the WebFiling and paper routes close for accounts (they stay open for other filings such as the confirmation statement). At the same time:
- Small companies and micro-entities must file a profit and loss account, with an option to keep it off the public register.
- Abridged accounts are withdrawn for small companies.
- Directors claiming an audit exemption must give an enhanced statement on the balance sheet identifying the exemption relied on.
If you currently type your accounts into WebFiling each year, the practical to-do is to move to a software filing route (or an accountant who files by software) before your first deadline falling after 1 April 2028. In the Leeds example above, the company's first accounts are due 10 March 2028, three weeks before the switch; its second-year accounts must go through software.
Common Mistakes Directors Make
- Filing at Companies House and forgetting HMRC. The CT600 with full accounts is a separate obligation with a separate deadline. HMRC will chase it, with penalties.
- Missing the confirmation statement. Form CS01 is a separate filing due at least every 12 months even if nothing has changed. It costs £50 online (£110 on paper). Our guide to filing a confirmation statement walks through it.
- Not signing the balance sheet. Companies House rejects unsigned accounts, and a rejection near the deadline can turn into a late filing penalty.
- Leaving the authentication code to the last week. A replacement code goes by post to the registered office. If you have changed accountants or moved office, sort it early.
- Assuming a loss-making or non-trading year means no filing. Accounts and a confirmation statement are due every year regardless.
What About Dormant Companies?
If your company has no significant transactions during the year (broadly: nothing beyond the initial share subscription, Companies House fees, and any late filing penalty), you can file dormant company accounts, which are a simplified balance sheet with a dormancy note. You still file with Companies House every year, and you still owe HMRC a corporation tax return unless you have told HMRC the company is dormant for tax purposes; the two definitions of dormant are not the same. The detail is in our guide to dormant company filing requirements.
Do You Need an Accountant to File Company Accounts?
Legally, no. A director can prepare and file the company's own accounts, and many micro-entities do exactly that with software. Practically, most directors benefit from professional help: an accountant makes sure the accounts comply with the right standard, claims the reliefs you might miss (capital allowances, R&D, trivial benefits), handles the two-CT600 first year correctly, and keeps every deadline. One late filing penalty or one missed relief usually costs more than the fee.
Our team at Holloway Davies handles the full cycle for clients across the UK: accounts preparation, the Companies House filing, the CT600, and the tax planning around them. If you would rather focus on running the business, speak to us about our accounts preparation service.
Checklist: What You Need Before You File
- Your company authentication code (for Companies House filing)
- Your company UTR (10-digit Unique Taxpayer Reference, for HMRC)
- Complete bookkeeping records for the year, reconciled to the bank
- A balance sheet approved and signed by a director
- Your accounting reference date and both filing deadlines in the diary
- Companies House and HMRC online logins (or software that files to both)
Final Advice
Filing company accounts is a legal obligation, not an administrative nicety, and the penalties are automatic on both sides. Get the first-year timeline written down on day one, because the 21-month first-accounts deadline and the split corporation tax periods are where new directors get caught. If turnover has passed £90,000 in any rolling 12 months, check the VAT registration threshold rules too. And if you plan to sell the company one day, clean, on-time accounts from the start make due diligence far smoother. Contact our team if you want the filing handled for you.