How to File Accounts with Companies House?

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Filing accounts with Companies House is an annual legal responsibility for UK limited companies, including startups that have made little money, recorded a loss or remained dormant.

For most private limited companies, accounts are due nine months after the financial year ends, while first accounts are commonly due 21 months after incorporation. Companies House accounts are separate from the Company Tax Return submitted to HMRC.

For founders filing in 2026, the old joint online service for filing company accounts and a Company Tax Return closed on 31 March 2026.

Companies House accounts can still be submitted through eligible online services, compatible commercial software or, for now, by post, depending on the account type.

Filing Accounts With Companies House in 2026: What Do Startups Need to Know?

The filing process is easier to manage when you separate four decisions: when you need to file, what type of accounts your company qualifies for, how you will submit them and what must separately go to HMRC.

Question	Typical Answer for a UK Private Company
Who must file accounts?	UK limited companies, including most dormant companies
First accounts deadline	Usually 21 months after incorporation
Later accounts deadline	9 months after the financial year ends
Corporation Tax payment	Usually 9 months and 1 day after the Corporation Tax accounting period ends
Company Tax Return	Usually 12 months after the Corporation Tax accounting period ends
Can accounts be filed online in 2026?	Yes, for eligible account types
Can commercial software be used?	Yes
Will software become compulsory?	Yes, from 1 April 2028
Are Companies House accounts and a confirmation statement the same?	No

A startup should therefore treat its Companies House deadline, Corporation Tax payment and Company Tax Return as separate compliance dates rather than assuming one submission covers everything.

Start With Your Filing Deadline, Not the Filing Form

One of the easiest mistakes for a new director to make is opening an accounting platform before confirming exactly when the company’s accounts are due.

For an established private company, Companies House normally allows nine months after the accounting reference period ends. Public companies normally have six months.

First accounts need more attention.

A new company’s first financial year generally starts on its incorporation date. Its first accounting reference date is normally the final day of the month in which the first anniversary of incorporation falls.

This means the first set of accounts frequently covers slightly more than 12 months.

If first accounts cover more than 12 months, a private company normally has until the later of:

21 Months From Incorporation
Three Months From The Accounting Reference Date

For example, suppose a startup incorporated on 14 February 2026. Its first accounting reference date would normally be 28 February 2027.

Its Companies House filing deadline would generally fall 21 months after incorporation, on 14 November 2027. Checking the date shown on the company’s Companies House record is sensible rather than calculating it from memory.

Can Your First Accounts Create Two Corporation Tax Periods?

This is one of the details that basic Companies House filing guides often overlook.

Companies House accounts can cover more than 12 months, particularly during a company’s first year. A Corporation Tax accounting period, however, cannot exceed 12 months.

As a result, a startup whose first statutory accounts cover more than 12 months may need to submit two Company Tax Returns covering the same overall period represented by one set of Companies House accounts.

That distinction matters because Companies House and HMRC are asking for related financial information under different legal reporting systems.

A founder who successfully files annual accounts with Companies House has therefore not necessarily completed the company’s Corporation Tax obligations.

What Accounts Does Your Startup Actually Need to File?

Not every company files the same level of financial information.

Company size is important because smaller businesses can currently use reduced reporting and disclosure provisions. The thresholds were increased for accounting periods beginning on or after 6 April 2025, making older articles that still quote £632,000 or £10.2 million thresholds outdated.

Micro-Entity Thresholds

A business normally qualifies as a micro-entity if it meets at least two of these conditions:

Test	Current Threshold
Annual Turnover	£1 Million Or Less
Balance Sheet Total	£500,000 Or Less
Average Employees	10 Or Fewer

Micro-entity accounts contain less detailed information than accounts prepared by larger companies and can currently benefit from certain small-company exemptions.

Small Company Thresholds

For accounting periods beginning on or after 6 April 2025, a company normally qualifies as small if it meets at least two of these conditions:

Test	Current Threshold
Annual Turnover	£15 Million Or Less
Balance Sheet Total	£7.5 Million Or Less
Average Employees	50 Or Fewer

Being below one threshold alone does not necessarily make the business a small company. The two-out-of-three test matters, and additional restrictions apply to certain businesses and corporate groups.

What Goes Into Statutory Accounts?

A normal set of statutory company accounts can include:

Balance Sheet showing what the company owns, owes and is owed at the end of the reporting period
Profit And Loss Account showing sales, costs and profit or loss during the period
Notes To The Accounts providing additional information behind the figures
Directors’ Report where required
Strategic Report where required
Auditor’s Report where an audit is required
Group Accounts where applicable

The balance sheet must be approved and signed by a director.

What is prepared for shareholders and what appears publicly on Companies House can differ for qualifying smaller companies under the current rules.

Small companies and micro-entities can currently file accounts while omitting the profit and loss account from the copy placed on the public register in qualifying circumstances. That system is scheduled to change in 2028.

How to File Accounts With Companies House Step by Step

For a startup director, the practical filing process begins months before pressing the submit button.

1. Confirm Your Accounting Reference Date

Check the company’s Companies House record and identify:

Financial Year End
Accounts Made-Up Date
Filing Deadline
Whether Previous Accounts Were Filed Late

Do this before preparing the final accounts because changing an accounting reference date can alter the deadline.

2. Reconcile Your Financial Records

Bring the bookkeeping up to date and check that transactions recorded in your accounts agree with supporting evidence.

Typically, this means reviewing bank transactions, invoices, expenses, payroll information, director transactions, loans, asset purchases and money invested into the company.

Poor records create problems much earlier than the Companies House submission itself.

Using suitable accounting software for small businesses can make reconciliation and financial reporting easier throughout the year rather than attempting to reconstruct everything immediately before the deadline.

3. Decide Which Reporting Regime Applies

Determine whether the company qualifies as:

Dormant
Micro-Entity
Small Company
Medium-Sized Company
Large Company

Do not select micro-entity accounts simply because the startup feels small. Eligibility depends on statutory criteria.

4. Prepare the Statutory Accounts

Your bookkeeping data needs to be converted into accounts that comply with the appropriate UK accounting and company-law requirements.

Very simple micro-entities may be comfortable preparing their own accounts, although an accountant becomes increasingly useful where a startup has investors, share transactions, loans, substantial assets, VAT, employees, overseas transactions or complex tax positions.

5. Get Director Approval

Annual accounts must be approved by the company’s directors before they are filed.

The balance sheet must identify the approving director and contain the required statements relevant to the reporting regime being used.

6. Choose the Correct Filing Route

Companies House currently supports different filing methods depending on the account type.

In 2026, the available routes can include:

Companies House Online Services
WebFiling For Certain Account Types
Compatible Commercial Software
Paper Filing Where Permitted

Companies House currently lists WebFiling for certain micro-entity and dormant accounts, while other account types may need a different online service or commercial software. More complex accounts, including many audited filings, generally require software.

This makes it important to check the filing method for your particular accounts rather than assuming every set can simply be uploaded through the same Companies House screen.

7. Submit Early Enough to Fix a Rejection

Submission is not something to leave until the final few minutes of the deadline.

Companies House can reject accounts that do not meet filing requirements. Paper accounts also take longer to process, and Companies House warns that a rejected filing does not automatically give the company additional time beyond its filing deadline.

Aim to submit early enough that an error can be corrected without turning a technical rejection into a late-filing penalty.

What Details Do You Need Before Filing Online?

One piece of information deserves particular attention: the company authentication code.

It is a six-character alphanumeric code connected to the company and is effectively used as an electronic authorisation for online filings.

Companies House sends replacement authentication codes by post, and current guidance says delivery can take up to 10 working days. Waiting until the filing deadline to request one is therefore risky.

Keep the code secure and only provide it to people authorised to file for the company, such as a trusted accountant.

Authentication Code vs Companies House Personal Code

The introduction of mandatory identity verification has created another potential source of confusion for founders.

These two codes are not interchangeable.

Code	What It Relates To
Company Authentication Code	The company and authority to submit online filings
Companies House Personal Code	An individual who has completed identity verification

The authentication code is associated with the company. A Companies House personal code is an 11-character code belonging to an individual after identity verification.

Mandatory identity verification for directors and people with significant control began being introduced from 18 November 2025. For existing directors, the transition is linked particularly closely to the company’s confirmation statement requirements.

This is another reason not to treat annual accounts and confirmation statements as the same filing.

Are Annual Accounts, Confirmation Statements and Tax Returns the Same Thing?

A startup can complete one annual filing and still remain overdue on another.

Requirement	Filed With	Main Purpose
Annual Accounts	Companies House	Report company finances
Confirmation Statement	Companies House	Confirm key company information
Company Tax Return	HMRC	Calculate and report Corporation Tax
Corporation Tax Payment	HMRC	Pay tax owed

The confirmation statement deals with information such as directors, registered office details, shareholders and people with significant control rather than the company’s annual financial performance.

In 2026, identity verification also affects confirmation statement compliance. Companies House says a company’s next confirmation statement must include the required identity-verification information for its directors during the transition.

A startup can complete one annual filing and still remain overdue on another.

Requirement	Filed With	Main Purpose
Annual Accounts	Companies House	Report company finances
Confirmation Statement	Companies House	Confirm key company information
Company Tax Return	HMRC	Calculate and report Corporation Tax
Corporation Tax Payment	HMRC	Pay tax owed

Has the Joint HMRC Filing Service Closed?

Founders who have previously filed accounts may remember an HMRC service that allowed eligible companies to file accounts and their Company Tax Return through one online process.

That service closed on 31 March 2026.

Since 1 April 2026, companies that previously relied on it need another solution for their HMRC Company Tax Return, normally commercial software. Companies House accounts can still be filed through the filing routes currently offered by Companies House.

Some commercial accounting products can handle both Companies House accounts and HMRC submissions, which can reduce duplicate work, but the underlying legal deadlines remain separate.

What Happens If You File Accounts Late?

Companies House late-filing penalties are automatic.

For a private limited company, the current penalty structure is:

How Late	Penalty
Not More Than 1 Month	£150
More Than 1 Month And Up To 3 Months	£375
More Than 3 Months And Up To 6 Months	£750
More Than 6 Months	£1,500

If accounts are late in two successive financial years, the penalty for the second consecutive late year is doubled.

Repeated failure is more serious than the financial penalty alone. Failure to deliver required accounts is an offence, directors can face enforcement action and Companies House can ultimately take steps towards removing a company from the register.

This makes filing particularly important for a startup that is no longer trading. Simply abandoning the company does not remove its filing responsibilities.

What If You Know You Cannot Meet the Deadline?

Do not wait until the deadline has passed before dealing with the problem. Companies House allows a business to apply for additional time when an unexpected event outside its control prevents the accounts being filed.

Examples could include a serious unexpected event or destruction of business records.

The important rule is that the extension application must be made before the normal filing deadline. If an extension is approved and the company files before the revised deadline, it can avoid the late-filing penalty.

Ordinary poor planning is not a good strategy for obtaining more time.

Can You Correct Accounts After Filing?

Discovering an accounting error after submission does not mean the public record can never be corrected.

Amended accounts can be submitted to Companies House. They must cover the same accounting period as the original filing and clearly indicate that they replace the earlier statutory accounts.

The original filing generally remains visible on the Companies House record alongside the amendment.

This is particularly relevant to startups that file quickly during an investment round and later discover that a transaction was incorrectly classified.

Material errors should normally be discussed with an accountant before amended accounts are filed.

Dormant Startups Still Have Filing Responsibilities

A company that has not started trading cannot simply ignore Companies House.

Dormant companies generally still need to file annual accounts and a confirmation statement, although their accounts can be significantly simpler.

This applies even where:

The Startup Has No Customers
No Revenue Has Been Earned
The Founders Have Paused The Project
The Business Has Never Properly Launched

Companies House expressly states that annual accounts are required from companies including dormant companies.

A different question is whether the company is dormant for Corporation Tax purposes. Companies House and HMRC definitions and procedures should not be assumed to be identical.

A Major Accounts Filing Change Is Coming in April 2028

A startup filing in 2026 should understand the current system, but it should also avoid building an accounting process that will become obsolete shortly afterwards.

Companies House has confirmed that from 1 April 2028, all UK companies will have to file annual accounts through commercial software in iXBRL format.

Web-based and paper accounts filing routes will close for annual accounts from that date.

The reforms also include significant changes for small companies and micro-entities.

From April 2028:

Commercial Software Filing Will Become Mandatory
Abridged Accounts Will Be Removed
Small Companies And Micro-Entities Will Have To Deliver A Profit And Loss Account
Qualifying Small Companies And Micro-Entities Will Be Able To Opt Out Of Publishing Their Profit And Loss Account On The Public Register
Audit Exemption Statements Will Be Strengthened

For founders choosing accounting systems now, software that can evolve with Companies House filing requirements may therefore be more useful than a process built entirely around manual year-end preparation.

A Practical Filing Routine for Growing Startups

The best way to avoid filing problems is to treat Companies House compliance as part of normal finance operations rather than an annual emergency.

During the year, reconcile bank accounts regularly, store invoices and receipts, document director loans correctly and keep shareholder transactions organised.

Around three months before the year end, check whether the business is approaching a company-size threshold or whether events such as fundraising, international expansion or group restructuring could change the accounts required.

After the year end, prepare the accounts early enough to resolve questions with an accountant well before the Companies House deadline.

Finally, confirm that Companies House has accepted the filing rather than assuming that pressing submit has completed the process.

Final Thoughts

Filing accounts with Companies House is relatively straightforward for many startups once the obligations are separated into manageable parts.

Know the company’s accounting reference date, identify the correct reporting regime, maintain reliable bookkeeping records and choose a filing method that supports the type of accounts you need to submit.

The biggest risk is usually not accounting complexity. It is allowing several different deadlines and systems to blur together.

Companies House annual accounts, the confirmation statement, Corporation Tax payment and the Company Tax Return each serve different purposes. Keeping those obligations on a compliance calendar gives founders much more control and reduces the likelihood of avoidable penalties.

With the joint HMRC filing service already closed and software-only Companies House accounts filing confirmed for April 2028, startups also have a strong reason to make digital financial records part of their operating process now rather than waiting until the new filing rules become compulsory.

Frequently Asked Questions

Do All Limited Companies Have to File Accounts With Companies House?

Most UK limited companies must file annual accounts, including companies that are dormant or have not traded. Limited exemptions can apply in particular circumstances.

When Are My First Companies House Accounts Due?

For many private limited companies whose first accounts cover more than 12 months, the deadline is normally 21 months after incorporation or three months after the accounting reference date, whichever gives more time.

Can I File My Own Limited Company Accounts?

Yes, directors can prepare and file their own accounts where they understand the applicable accounting requirements. Complex transactions, investors, groups or uncertainty over the correct reporting regime may make professional advice worthwhile.

Can I Still File Companies House Accounts Online in 2026?

Yes. Companies House still provides online filing for eligible account types, while commercial software is required or available for others.

Can I File Companies House Accounts and My Company Tax Return Together?

The previous HMRC joint filing service closed on 31 March 2026. Some commercial software can handle submissions to both Companies House and HMRC, but the filings and deadlines remain legally separate.

What Is the Companies House Late Filing Penalty?

For a private company, the penalty starts at £150 when accounts are no more than one month late and can rise to £1,500 after six months. Consecutive late filing can result in the penalty being doubled.

Does a Dormant Startup Still Need to File Accounts?

Yes. Dormant companies generally still have annual Companies House filing obligations, although they may qualify to submit simpler dormant company accounts.

Will Companies House Require Accounting Software?

Yes. Companies House has confirmed that commercial software filing will become compulsory for annual accounts from 1 April 2028, when paper and Companies House web-based accounts filing will close.