Setting up a limited company takes less than a day. Understanding what you have to file afterwards, who you have to file it with, and when, takes considerably longer. New directors are often surprised to find that they are dealing with two separate government bodies, Companies House and HMRC, each with its own forms, deadlines and penalties, and that neither will automatically remind the other when something is missed.
This guide is a plain English introduction to the core filing obligations of a UK limited company. It explains what Companies House and HMRC each need from you, what statutory accounts, the Corporation Tax return and the confirmation statement actually are, and how the deadlines fit together. A worked example follows one new company through its first two years, so you can see exactly how the dates are calculated.
Disclaimer: This guide is for general information only and reflects Companies House and HMRC requirements, deadlines and penalties current at the time of writing in October 2026. Filing rules are changing under the Economic Crime and Corporate Transparency Act and HMRC's digital programme, and your exact deadlines depend on your company's own dates. Always confirm your specific obligations with your accountant.
In This Guide
- What a limited company is, in brief
- Companies House versus HMRC: who needs what from you
- Statutory accounts: what they are and when they are due
- The Corporation Tax return (CT600): what it is and when it is due
- The confirmation statement: what it is and when it is due
- The other regular obligations you need to know about
- A worked example: a new company's first filing calendar
- Frequently asked questions
1. What a Limited Company Is, in Brief
A limited company is a separate legal person, distinct from the people who own and run it. It can enter into contracts, own property, employ people, borrow money and owe tax in its own name. That separation is what gives shareholders limited liability. In most cases, if the company cannot pay its debts, the shareholders' personal assets are protected and they lose only what they have invested in their shares.
That protection comes with a price, which is transparency and paperwork. Because a company is a separate entity, it has to keep its own records, prepare its own accounts, pay its own tax, and put certain information on a public register. The money in the company's bank account belongs to the company, not to you, even if you own all the shares. You can only take it out in recognised ways, such as salary, dividends, expense reimbursements or by repaying money you have lent to the company. Anything else is likely to create a director's loan account, which has its own tax rules.
Two roles are worth separating clearly. Shareholders, also called members, own the company. Directors run it, and have legal duties under the Companies Act 2006, including responsibility for making sure filings are made on time. In many small companies the same person is both, but the roles carry different rights and responsibilities. If you are still deciding whether a company is the right structure, our guide to choosing between a sole trader and a limited company sets out the pros and cons.
2. Companies House Versus HMRC: Who Needs What From You
The single most useful thing a new director can understand is that Companies House and HMRC are separate organisations with separate jobs.
Companies House is the registrar of companies. Its role is to keep the official public register of every UK company, so that anyone dealing with a company can check who runs it, who controls it and what its financial position looks like. It is not a tax authority. It needs your statutory accounts each year, a confirmation statement at least once a year, and updates whenever certain details change, such as a new director or a change of registered office. Most of what you file with Companies House becomes publicly available, free of charge, to anyone who searches your company name.
HMRC is the tax authority. It needs to know about your company so it can collect Corporation Tax on profits, and, depending on your circumstances, PAYE and National Insurance on salaries, VAT on sales, and Construction Industry Scheme deductions. What you file with HMRC is confidential and does not appear on any public register.
The two bodies do share some information, and both receive a copy of your accounts, but they are not a single system. Filing your accounts with Companies House does not file your tax return with HMRC, and paying HMRC does not satisfy Companies House. Each has its own deadline, its own penalty regime and its own login. Missing a Companies House deadline triggers a Companies House penalty, and missing an HMRC deadline triggers an HMRC penalty, even if everything else is in order.
The practical way of filing has also changed. HMRC closed its free online Corporation Tax filing service in 2026, so returns now need to be filed using commercial software, and Companies House is moving steadily towards software based filing as well. Our article on the end of free HMRC filing explains what this means in practice.
Worked Example 1: What Is Public and What Is Private
Bluebell Design Ltd, the design agency used as the example in our guide to reading your company accounts, made turnover of £240,000 and profit after tax of £41,210 in its first year. Because it qualifies as a micro entity, it can file very simplified accounts with Companies House, consisting mainly of a balance sheet with limited notes. Anyone searching the public register can see Bluebell's net assets of £11,310 and its share capital, along with the names of its director and the person with significant control, Ellie, her month and year of birth and a service address.
HMRC, by contrast, receives Bluebell's full accounts, including the profit and loss account, along with its Corporation Tax computation and CT600 return. None of that is published. This split between public and private information is why many small company owners are relieved to learn that their turnover and profit are not, at present, visible to competitors or clients. Changes planned under the Economic Crime and Corporate Transparency Act are expected to require small companies to file a profit and loss account with Companies House from April 2028, with an option for it not to be published, as explained in our article on the profit and loss filing changes.
3. Statutory Accounts: What They Are and When They Are Due
Statutory accounts, also called annual accounts or year end accounts, are the formal financial statements a company must prepare each year under the Companies Act 2006. They must be approved by the board of directors, signed on behalf of the board, circulated to shareholders and filed with Companies House.
For a typical small company, full statutory accounts include a balance sheet, a profit and loss account, notes explaining the figures and the accounting policies used, and in some cases a directors' report. Our companion guide on how to read your company accounts explains what each statement shows.
How much you have to file depends on your company's size
What you send to Companies House depends on which size category your company falls into. Following the threshold increases from April 2025, a company is generally a micro entity if it meets at least two of the following conditions: turnover of no more than £1 million, a balance sheet total of no more than £500,000, and no more than 10 employees on average. A company is generally small if it meets at least two of the following: turnover of no more than £15 million, a balance sheet total of no more than £7.5 million, and no more than 50 employees. Our article on the new company size thresholds explains the rules in more detail.
Micro entities and small companies can usually file simplified accounts with Companies House and can usually claim exemption from audit. Whatever version is filed publicly, the company must still prepare full accounts for its shareholders, and HMRC will need them to support the tax return.
Your accounting reference date
Every company has an accounting reference date, which is the date its financial year ends. When a company is formed, this is set automatically as the last day of the month in which the anniversary of incorporation falls. A company incorporated on 15 May will have an accounting reference date of 31 May. Many companies change this to a date that suits them better, such as 31 March to align with the tax year, which can be done by filing a simple form with Companies House, subject to some limits.
When statutory accounts are due
For a private company, accounts must reach Companies House within nine months of the accounting reference date. A company with a 31 March year end must file by 31 December.
The first set of accounts follows a different rule. Because a company's first accounting period can be longer than twelve months, the first accounts are generally due 21 months after the date of incorporation, or three months after the accounting reference date if that is later. In practice, for most new companies, the 21 month deadline applies.
Penalties for late filing
Companies House charges automatic penalties for late accounts, which cannot be avoided simply by paying promptly. For private companies, the penalty is £150 if accounts are up to one month late, £375 if they are between one and three months late, £750 if they are between three and six months late, and £1,500 if they are more than six months late. The penalty is doubled if accounts are filed late in two consecutive years. Persistent failure to file can also lead to the company being struck off the register, and directors can be prosecuted.
4. The Corporation Tax Return (CT600): What It Is and When It Is Due
The CT600 is the company's Corporation Tax return, filed with HMRC. It reports the company's taxable profit for an accounting period and calculates the tax due. It must be filed online, together with a copy of the statutory accounts and a tax computation, both in a tagged digital format called iXBRL, which commercial accounting and tax software produces automatically.
The tax computation is the bridge between the accounting profit in your statutory accounts and the taxable profit HMRC charges tax on. It adds back items that are not allowed for tax, such as depreciation and client entertaining, and deducts allowances that are, such as capital allowances on equipment. This is why the tax charge in your accounts is rarely a neat percentage of your accounting profit.
Corporation Tax rates
For the current financial year, companies with taxable profits of £50,000 or less pay Corporation Tax at the small profits rate of 19%. Companies with profits above £250,000 pay the main rate of 25%. Between those two limits, marginal relief applies, producing an effective rate somewhere between the two. The limits are reduced proportionately for shorter accounting periods and are shared between associated companies.
Registering with HMRC
A new company must tell HMRC within three months of starting to do business, which includes buying, selling, employing someone, advertising or renting premises. HMRC will then send a Unique Taxpayer Reference and, each year, a notice to file a Corporation Tax return.
Paying versus filing: two different deadlines
This is the point that catches out more new directors than any other. Corporation Tax has a payment deadline and a filing deadline, and the payment comes first.
For most small and medium sized companies, Corporation Tax must be paid within nine months and one day of the end of the accounting period. A company with a 31 March year end must pay by 1 January.
The CT600 return itself must be filed within twelve months of the end of the accounting period. The same company must file by 31 March of the following year.
So the tax is due three months before the return is due. Waiting until the filing deadline to find out how much you owe means paying late and incurring interest. Companies with very large profits, above £1.5 million, pay by quarterly instalments instead.
Accounting periods and Corporation Tax periods
A Corporation Tax accounting period can never be longer than twelve months, even though a company's first set of statutory accounts can be. Where the first accounts cover more than twelve months, the company must file two CT600 returns, one for the first twelve months and one for the remaining period, and each has its own payment deadline. The worked example in section 7 shows how this works.
Penalties and interest
From 1 April 2026, HMRC's fixed penalties for late Corporation Tax returns doubled. A return filed one day late now attracts a £200 penalty, with a further £200 if it is more than three months late. If the return is more than six months late, HMRC estimates the tax and adds a further penalty of 10% of the unpaid tax, with another 10% if it is more than twelve months late. Higher fixed penalties apply if returns are late three times in a row. Separately, interest is charged on Corporation Tax paid late, at the Bank of England base rate plus 4%. Our article on the Corporation Tax late filing penalties sets out the full schedule.
5. The Confirmation Statement: What It Is and When It Is Due
The confirmation statement, which replaced the old annual return in 2016, is a short filing with Companies House confirming that the information on the public register about your company is correct and up to date. It is not a set of accounts and contains no financial information beyond share capital.
When you file it, you confirm or update details such as the registered office address, the directors, the shareholders and their shareholdings, the share capital, the people with significant control, and the company's business activity, known as its SIC code. Since March 2024, companies must also have a registered email address for Companies House correspondence, and must confirm that their intended future activities are lawful.
When it is due
A confirmation statement must be filed at least once every twelve months. Each company has a review period, which for a new company ends on the anniversary of incorporation, and the statement must be filed within 14 days after the end of that period. Your company's next due date is shown on its Companies House record. You can file earlier, which resets the review period, and many companies choose to file at the same time as reporting another change.
A filing fee applies each year. Unlike the accounts, late confirmation statements do not attract an automatic financial penalty, but failing to file is a criminal offence for the company and its directors, and Companies House may begin the process of striking the company off the register. In practice, this can create serious problems, from a bank freezing the company's account to the company's assets passing to the Crown.
Identity verification
From 18 November 2025, every director and person with significant control must verify their identity with Companies House. Existing directors and people with significant control are generally required to do this by the time of the company's first confirmation statement due after that date, which means many companies are working through this requirement as their annual confirmation statements fall due. Our guide to Companies House identity verification explains the process and how CoreAcc, as a registered Authorised Corporate Service Provider, can verify you.
6. The Other Regular Obligations You Need to Know About
Statutory accounts, the CT600 and the confirmation statement are the three core annual filings for every company. Depending on what your company does, several others will also apply.
If the company pays any salaries, including to its directors, it must register as an employer with HMRC and report each payment through Real Time Information payroll on or before payday, paying the PAYE and National Insurance due by the 22nd of the following month when paying electronically.
If the company is registered for VAT, which is compulsory once taxable turnover exceeds £90,000 in any rolling twelve month period, it must usually file VAT returns every quarter through Making Tax Digital compatible software, generally within one month and seven days of the end of each quarter.
If the company works in construction, it may need to file monthly Construction Industry Scheme returns.
Directors are not automatically required to file a personal Self Assessment return simply because they are directors, but most directors who take dividends above the dividend allowance, or who have other untaxed income, will need to. Personal tax returns are due by 31 January following the end of the tax year.
Companies must also notify Companies House of changes, generally within 14 days, including the appointment or resignation of a director, changes to a director's details, and changes to people with significant control. A change of registered office address takes effect once Companies House registers it. Companies must keep certain statutory records, such as a register of members, and must keep accounting records for at least six years for HMRC purposes. Some register requirements are changing under the Economic Crime and Corporate Transparency Act, so it is worth confirming the current position with your accountant.
Our 2026 Tax Calendar brings many of the key HMRC dates together in one place.
7. A Worked Example: A New Company's First Filing Calendar
Worked Example 2: Ashby Lane Consulting Ltd
Ashby Lane Consulting Ltd is incorporated on 15 May 2025 and starts trading the same day. Its directors do not change its accounting reference date, so it is set automatically to 31 May, the last day of the month in which the anniversary of incorporation falls.
Its first statutory accounts therefore cover the period from 15 May 2025 to 31 May 2026, slightly more than twelve months. Because this is the company's first set of accounts, they are due at Companies House 21 months after incorporation, which is 15 February 2027.
Because a Corporation Tax accounting period cannot exceed twelve months, that single set of accounts is split into two Corporation Tax periods. The first runs from 15 May 2025 to 14 May 2026, and the second covers the remaining short period from 15 May 2026 to 31 May 2026.
Each period has its own payment deadline, nine months and one day after it ends. Corporation Tax for the first period must be paid by 15 February 2027, and for the second short period by 1 March 2027. Both CT600 returns must be filed within twelve months of the end of the period covered by the statutory accounts, which is 31 May 2027.
Ashby Lane's first confirmation statement covers the review period ending on the first anniversary of incorporation, and must be filed within 14 days of that date, in May 2026. The exact date is shown on the company's Companies House record.
From the second year onwards, the calendar settles into a simple pattern. The financial year runs from 1 June to 31 May. Corporation Tax is due by 1 March each year. Accounts are due at Companies House by the end of February each year, nine months after the year end. The CT600 is due by 31 May each year. The confirmation statement is due each May.
Notice that, in this example, the first set of accounts is due at Companies House on the same day as the first Corporation Tax payment, and well before the CT600 filing deadline. Many companies therefore aim to finalise their accounts and tax computation together, several months after the year end, so that the tax payment can be calculated accurately and paid on time.
Worked Example 3: The Cost of Leaving It Late
Suppose that, in its second year, Ashby Lane's director is busy with clients and the year end paperwork slips. The accounts for the year ended 31 May 2027 reach Companies House two months after the deadline. Companies House charges a penalty of £375. The CT600 is filed four months late, triggering two HMRC fixed penalties of £200 each, a total of £400. The Corporation Tax of £12,000 is also paid four months late, and interest at 7.75%, being the Bank of England base rate of 3.75% plus 4%, adds around £310.
In total, the delay costs the company more than £1,000 in penalties and interest, none of which is deductible for Corporation Tax, and the late filings sit on HMRC's and Companies House's records, which can affect how HMRC views the company in future. Every one of those costs could have been avoided by preparing the year end accounts a few months after the year end rather than at the last minute.
Frequently Asked Questions
What is the difference between Companies House and HMRC?
Companies House is the registrar of companies and keeps the public register of company information, including accounts and details of directors and owners. HMRC is the tax authority and collects Corporation Tax, PAYE, VAT and other taxes. They are separate organisations with separate deadlines and penalties, and filing with one does not satisfy the other.
When are my first company accounts due?
For most new private companies, the first accounts are due at Companies House 21 months after the date of incorporation. After that, accounts are due nine months after each accounting reference date.
When do I pay Corporation Tax?
For most small and medium sized companies, Corporation Tax is due nine months and one day after the end of the accounting period. This is three months before the CT600 return itself is due, so you need to know your tax figure well before the filing deadline.
What is a CT600?
The CT600 is the company's Corporation Tax return. It is filed online with HMRC each year, along with the statutory accounts and a tax computation, and must be filed within twelve months of the end of the accounting period.
What is a confirmation statement and do I have to file one if nothing has changed?
The confirmation statement confirms that the information Companies House holds about your company is correct. It must be filed at least once every twelve months even if nothing has changed, because its purpose is to confirm that the register is up to date.
Can I file my own company accounts?
You can, provided you have suitable software and the knowledge to prepare accounts and a tax computation correctly. HMRC's free filing service has closed, so returns must now be filed through commercial software. Many directors choose to use an accountant, not least because errors can lead to penalties, overpaid tax or an HMRC enquiry.
Does a dormant company still need to file?
Yes. A dormant company that is not trading must still file annual accounts and a confirmation statement with Companies House. If HMRC has been told that the company is dormant for Corporation Tax purposes, it may not need to file a CT600 unless HMRC sends a notice to file.
What happens if I miss a Companies House deadline?
Late accounts attract automatic penalties from £150 up to £1,500 for private companies, doubled if accounts are late two years in a row. Failing to file accounts or a confirmation statement can also lead to the company being struck off the register and its directors being prosecuted.
Do I need to file a personal tax return as a director?
Not automatically. However, most directors who receive dividends above the dividend allowance, or who have other income that is not taxed at source, will need to file a Self Assessment return by 31 January following the end of the tax year.
Can I change my company's year end?
Yes, in most cases, by filing a form with Companies House to change the accounting reference date. There are limits on how often a year end can be extended and on how long an accounting period can be, so it is worth taking advice before making a change.
What CoreAcc Accountants Can Help You With
CoreAcc Accountants takes care of the full compliance cycle for limited companies, from Companies House identity verification and confirmation statements through to statutory accounts, Corporation Tax computations and CT600 returns, payroll, VAT and directors' Self Assessment returns. For new companies, we set out every deadline from day one, explain what each filing is for, and keep track of dates so nothing is missed. We prepare accounts well ahead of the deadlines, so you know your Corporation Tax bill in good time to pay it, and we explain your figures in plain English so the accounts are useful to you as well as to Companies House and HMRC.
If you would like to understand what your accounts are telling you, our companion guide on how to read your company accounts explains the profit and loss account, balance sheet, cash flow and retained earnings, using the same plain English approach.
Get in Touch
If you have just formed a company, are thinking of incorporating, or are not confident that all your company's filings are up to date, contact CoreAcc Accountants. We will map out your company's deadlines, confirm what has been filed and what is outstanding, and take the compliance off your hands so you can focus on running the business.
CoreAcc Accountants is an ACCA accredited firm of Chartered Certified Accountants based in Borehamwood, Hertfordshire. This guide was last updated in October 2026 and reflects Companies House and HMRC requirements, deadlines and penalties current at the time of writing. It does not constitute professional or legal advice. Always seek specific advice tailored to your individual circumstances.
