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 rating, and potential director disqualification.

This guide walks you through exactly how to file company accounts in the UK. It covers what you need to prepare, where to send it, the deadlines that matter, and what happens if you get it wrong. Whether you run a single-director consultancy in Shoreditch or a four-employee manufacturing firm in the Birmingham Jewellery Quarter, the process is 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 given financial year. They include:

  • A profit and loss account (income statement)
  • A balance sheet
  • Notes to the accounts (explanatory notes)
  • A director's report (for larger companies, though many small companies choose to prepare one)

These accounts must give a true and fair view of your company's affairs. They are prepared from your bookkeeping records and must comply with UK GAAP (Generally Accepted Accounting Practice) or FRS 102, depending on your company size.

Who Needs to File Company Accounts?

Every private limited company (Ltd) registered at Companies House must file accounts each year. This includes:

  • Single-director companies
  • Micro-entities (turnover up to £632,000, balance sheet total up to £316,000, average employees up to 10)
  • Small companies (turnover up to £10.2 million, balance sheet total up to £5.1 million, average employees up to 50)
  • Medium and large companies
  • Dormant companies (though the filing requirements are simpler)

Sole traders and partnerships do not file company accounts. They report through self assessment using an SA100 and SA103 (self-employment pages) or SA800 (partnership return). If you are a sole trader reading this, you are not required to file with Companies House. But if you have recently incorporated, the rules change immediately.

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).
  • HMRC receives your corporation tax return (form CT600) plus the full accounts.

For small and micro companies, you can file abridged or filleted accounts at Companies House. This means you omit certain details (like the profit and loss account or director's report) from public view. But HMRC still gets the full set of accounts behind the scenes. You cannot hide turnover from HMRC.

Deadlines: What You Cannot Afford to Miss

The deadlines are strict. There is no grace period for first-time filers.

  • Companies House deadline: 9 months after your accounting reference date (usually your year-end date). For example, if your year-end is 31 March 2025, your accounts are due by 31 December 2025.
  • HMRC deadline (corporation tax): 12 months after the end of the accounting period. But payment of corporation tax is due 9 months and 1 day after the year-end. You must file the return (CT600) within 12 months, but you must pay the tax earlier.

Your accounting reference date is set when you incorporate. You can change it by filing a form AA01 with Companies House, but only within certain limits. Most companies keep their year-end at 31 March, 30 April, or 31 December for simplicity.

Step-by-Step: How to File Company Accounts in the UK

Step 1: Prepare Your Accounts from Your Bookkeeping Records

Before you file anything, your accounts must be prepared. This means taking your raw bookkeeping data (sales invoices, purchase receipts, bank statements, payroll records) and turning it into a set of statutory accounts.

Most small companies use accounting software like Xero, FreeAgent, QuickBooks, or Sage 50. These tools can generate draft accounts automatically. But the final accounts must comply with UK accounting standards. If you are not confident preparing accounts yourself, an ICAEW-qualified accountant like our team at Holloway Davies will handle this for you.

The accounts must include a balance sheet signed by a director. The director's signature confirms the accounts are approved. Without that signature, Companies House will reject the filing.

Step 2: Decide Which Filing Format to Use at Companies House

Small and micro companies have options. You can file:

  • Full accounts (everyone can see everything)
  • Abridged accounts (you omit the profit and loss account from public view)
  • Filleted accounts (you omit the profit and loss account and director's report)

Micro-entities can file even simpler accounts with fewer notes. The trade-off is privacy versus simplicity. Most directors prefer filleted accounts to keep turnover and profit figures off the public register. Competitors and customers can search Companies House for free, so privacy matters.

Step 3: File Your Accounts with Companies House

You can file online through the Companies House WebFiling service or using third-party software. Most accountants file using software that connects directly to Companies House (Xero, FreeAgent, and Iris all offer this).

You will need your company authentication code. This is a 6-character code issued when you incorporated. If you have lost it, you can request a new one through the Companies House online service. It takes a few days to arrive by post.

The filing itself takes about 10 minutes once the accounts are ready. You upload the accounts as a PDF or use the online form. Companies House confirms receipt immediately and updates the public register within 24 hours.

Step 4: File Your Corporation Tax Return with HMRC

This is the second filing. You submit form CT600 through HMRC's online service or using accounting software. The CT600 includes:

  • Company details and accounting period
  • Profit and loss figures
  • Tax adjustments (disallowable expenses, capital allowances, etc.)
  • Tax calculation (how much corporation tax you owe)
  • Any reliefs or claims (R&D tax credits, capital allowances, group relief)

You must attach the full accounts (not the filleted version) to the CT600. HMRC sees everything. If your accounts are complex, you may also need to submit an R&D AIF (Additional Information Form) if you are claiming R&D tax credits.

Step 5: Pay Your Corporation Tax

Payment is due 9 months and 1 day after your year-end. If your year-end is 31 March 2025, payment is due by 1 January 2026. You pay through the HMRC online banking system using your company's 10-digit UTR number as the reference.

If your taxable profits exceed £1.5 million, you must pay in quarterly instalments. This affects about the top 1% of companies, so most small businesses pay in one lump sum.

Penalties for Late Filing

Companies House penalties are automatic. There is no warning letter. The penalties are:

  • Up to 1 month late: £150
  • 1 to 3 months late: £375
  • 3 to 6 months late: £750
  • 6 or more months late: £1,500

These double for public limited companies (PLCs). Late filing also means your company's credit rating takes a hit. Banks, suppliers, and insurers check Companies House records. A late filing flag makes you look unreliable.

HMRC penalties for late corporation tax returns start at £100 for the first day, then escalate. Interest accrues on unpaid tax from the due date.

Common Mistakes Directors Make

I see the same errors year after year. Here are the most frequent:

  • Filing the wrong accounts. Directors file abridged accounts at Companies House but forget HMRC still needs the full set. HMRC will chase you for the missing information.
  • Missing the confirmation statement. This is separate from the accounts. You must file a confirmation statement (form CS01) every 12 months, even if nothing has changed. It costs £13 online. Many directors confuse it with the annual accounts and miss the deadline.
  • Not signing the balance sheet. Companies House will reject the filing if the director's signature is missing. This can delay the process and trigger a late filing penalty.
  • Using the wrong authentication code. If you have changed accountants or lost the code, request a new one well before the deadline. The postal delay can catch you out.

Do You Need an Accountant to File Company Accounts?

Legally, no. You can file your own accounts as a director. Many micro-entities and small companies do exactly that using software like FreeAgent or Crunch.

Practically, most directors benefit from professional help. An accountant ensures the accounts comply with UK GAAP, identifies tax reliefs you might miss (capital allowances, R&D credits, trivial benefits), and keeps you on the right side of HMRC. The cost of an accountant is usually less than the cost of one penalty or one missed tax relief.

Our ICAEW qualified team at Holloway Davies handles the full filing process for clients across the UK. We prepare the accounts, file with Companies House, submit the CT600, and advise on tax planning. If you would rather focus on running your business, speak to us about our accounts preparation service.

What About Dormant Companies?

If your company has no significant transactions during the year (no income, no expenses except filing fees), you can file dormant company accounts. These are simpler. You file a balance sheet only, with a note confirming the company is dormant.

You still need to file with Companies House. And you still need to file a corporation tax return with HMRC (unless you have notified HMRC that the company is dormant for tax purposes). Many directors forget the HMRC step and incur penalties.

Checklist: What You Need Before You File

  • Your company authentication code (for Companies House online filing)
  • Your company UTR (10-digit Unique Taxpayer Reference, for HMRC filing)
  • Your company's accounting software records (or manual accounts)
  • A signed balance sheet (director's signature)
  • Confirmation of your accounting reference date and filing deadline
  • Your Companies House and HMRC online logins

Filing Deadlines at a Glance

Year-end 31 March 2025:

  • Companies House accounts due: 31 December 2025 (9 months)
  • Corporation tax payment due: 1 January 2026 (9 months + 1 day)
  • CT600 return due: 31 March 2026 (12 months)

Year-end 30 April 2025:

  • Companies House accounts due: 31 January 2026
  • Corporation tax payment due: 1 February 2026
  • CT600 return due: 30 April 2026

Final Advice

Filing company accounts is a legal obligation, not an administrative nicety. The penalties for getting it wrong are real and they escalate quickly. If your turnover crossed £90,000 in the last 12 months, you may also need to register for VAT. If you are planning to sell your company in the next few years, keeping clean accounts from day one makes due diligence far smoother.

For most directors, the smart move is to outsource the filing to a qualified accountant. The cost is modest compared to the risk of penalties, missed deadlines, or a damaged credit rating. Contact our team if you need help preparing or filing your company accounts.