Companies House Filing Calendar for UK Startups: Key Dates, Deadlines and Checklist

A Founder's Calendar for Companies House Filing Deadlines

Juggling product development, fundraising, and your first hires leaves little time for administrative tasks. Yet, UK Companies House filing deadlines are non-negotiable. Missing them triggers automatic fines and, in severe cases, can put your company at risk of being struck off. Aligning your bookkeeping in Xero with your accountant's schedule to meet these dates can feel complex when you have no CFO. The good news is that for most pre-seed to Series B startups, compliance can be managed with a simple, predictable calendar. This guide maps out your core obligations and builds a practical timeline based on your startup's lifecycle.

Your Three Core Companies House Filing Obligations

For a UK startup, your legal responsibilities to Companies House boil down to three distinct types of filings. Understanding the difference between them is the first step to building a reliable compliance calendar and avoiding late filing penalties. The reality for most early-stage businesses is more pragmatic: these are not meant to be burdensome, but simple check-ins and reports designed to keep your public record accurate.

1. The Confirmation Statement (CS01): Your Annual Check-in

This is your annual declaration that all the information Companies House holds about your company is correct. It confirms details like your registered office address, company directors, and shareholder information. The filing itself is straightforward, but the timing is crucial. A Confirmation Statement (CS01) is due at least once every 12 months. This period is known as the 'review period'. After your review period ends, you have a 14-day window to file the Confirmation Statement. Think of this as a simple health check to confirm nothing significant has changed, or to officially record changes that have occurred throughout the year.

2. Statutory Accounts: Your Annual Financial Report Card

This is your company's financial report card. It includes a balance sheet and, depending on your company's size, a profit and loss account. For early-stage startups in SaaS, Biotech, or Deeptech, the good news is you can typically file simpler accounts. Early-stage startups can typically file simpler 'micro-entity' or 'small company' accounts, which require less detail. You can review the specific rules for micro-entity and small company accounts for guidance. The deadline is fixed: Statutory Accounts are due 9 months after a company's financial year-end (Accounting Reference Date or ARD). This is a hard deadline and the one that most often catches founders out, as it requires coordination with your accountant well in advance.

3. Event-Driven Updates: The PSC Register

Unlike the other two, this filing is not based on an annual date but is triggered by specific events, most commonly a funding round. It relates to your register of 'People with Significant Control' (PSC). A Person with Significant Control (PSC) is an individual holding more than 25% of the shares or voting rights. When your cap table changes significantly after an investment, you may have new PSCs. The law requires a two-step update process: a company has 14 days to update its internal register, and another 14 days to notify Companies House. For more on the PSC regime and company obligations, see this PSC regime guide or our guide to maintaining the PSC register.

Building Your Startup Compliance Calendar: A Lifecycle View

Your UK company filing requirements evolve as your startup grows. Instead of a static list of dates, it’s more effective to view your obligations through the lens of your company’s lifecycle: from the day you incorporate, to your first funding round, and finally into a predictable annual rhythm.

Stage 1: Incorporation and Your First Year's Deadlines

The moment your company is incorporated, Companies House sets two important future dates. Your first task is to find these dates and put them in your calendar.

Your Accounting Reference Date (ARD) is your financial year-end. For a new company, a company's first ARD is automatically set for the end of the month, one year after its incorporation date. For example, if you incorporated on 10 March 2024, your first ARD will be 31 March 2025. This date is your anchor for your annual accounts deadline.

However, your very first set of accounts gets an extended deadline. To give new businesses time to get organised, a company's first set of statutory accounts are due 21 months after the incorporation date. Using the same example, a company incorporated on 10 March 2024 has until 9 December 2025 to file its first accounts.

Your first Confirmation Statement will be due 12 months after incorporation, with the 14-day filing window applied. So for our 10 March 2024 company, the statement is due by 24 March 2025.

Stage 2: Post-Funding Round PSC Register Updates

Let’s consider a common scenario for a Deeptech startup. You have just closed your £750,000 seed round. The deal brings in a new lead investor who now owns 30% of the company. This immediately triggers a PSC update. The key is to treat this as an event, not a piece of admin to be done later. The moment the shares are officially issued, your 28-day countdown begins: 14 days to update your internal company registers, and another 14 to file the update with Companies House. Rapid changes in share ownership make this easy to overlook, but non-compliance can create issues during future due diligence. What founders find actually works is tasking their lawyer handling the fundraise to complete the filings as part of the closing checklist. You can also see our guide to share capital filing requirements.

Stage 3: Establishing an Annual Filing Rhythm

After your first year, your Companies House deadlines settle into a predictable annual pattern. Your annual compliance rhythm has two key dates: your Confirmation Statement deadline and your Statutory Accounts deadline. To avoid a last-minute scramble, it’s crucial to establish a workflow with your accountant. The 9-month window after your ARD should not be seen as a 9-month delay. In practice, we see that the most organised founders start the process almost immediately after their year-end.

A typical 9-month accounts preparation workflow looks like this:

1. Months 1-2: You finalise all bookkeeping entries for the year in Xero or similar accounting software.
2. Month 3: Your accountant begins their review and requests any missing information or clarifications.
3. Months 4-5: You and your accountant collaborate to resolve queries and finalise the numbers.
4. Month 6: Your accountant prepares the draft statutory accounts for your review.
5. Month 7: You review and approve the draft accounts.
6. Month 8: Your accountant finalises and submits the accounts to Companies House.
7. Month 9: This is the final filing deadline.

This structured approach turns a stressful deadline into a manageable process, ensuring your focus remains on growing the business.

Your 30-Minute Compliance Check: A Practical Checklist

Managing your Companies House obligations does not require a finance team, just a proactive system. For any UK startup founder, from E-commerce to Professional Services, a simple monthly check-in can prevent nearly every common compliance failure.

Here’s how to build your 30-minute check:

1. Find Your Dates (5 Mins): Your first and most important step is to know your deadlines. You can find all key dates for your company instantly on the official UK government portal. Use the Companies House Service lookup page: https://find-and-update.company-information.service.gov.uk/. Find your next accounts due date and confirmation statement due date.
2. Calendar Your Deadlines (10 Mins): Put these dates into your calendar with multiple reminders. For your statutory accounts, set a reminder for the day after your ARD to contact your accountant. For your confirmation statement, set a reminder one month before it is due.
3. Review Significant Changes (15 Mins): Once a month, ask a simple question: did our ownership or directorship change? If you raised a funding round, issued new share options, or appointed a new director, that is an event-driven trigger. If the answer is yes, contact your accountant or lawyer immediately to handle the necessary filings.

By turning compliance from a dreaded annual event into a small, recurring task, you can ensure your company remains in good standing, allowing you to focus on what truly matters: building your startup. For broader context, visit the Reporting Obligations hub.

Frequently Asked Questions

Q: What are the late filing penalties for annual accounts?

A: Automatic civil penalties for private companies start at £150 if accounts are one month late and increase to £1,500 for accounts over six months late. Persistent failure to file is a criminal offence and can lead to director prosecution and the company being struck off the register.

Q: Can I change my company's Accounting Reference Date (ARD)?

A: Yes, you can change your company's ARD. This is often done to align your financial year with the calendar year (31 December) or with a new parent company's reporting schedule. You can shorten your accounting period as needed, but you can typically only extend it once every five years.

Q: What happens if I miss the Confirmation Statement deadline?

A: While there is no automatic financial penalty for a late Confirmation Statement, failing to file is a criminal offence. The company and its directors can be prosecuted. Companies House may also begin the process to dissolve the company and strike it from the official register, putting your business at risk.