What Are All My First Year Deadlines with HMRC and Companies House

Introduction

The first year of running a business can feel overwhelming. Between registering your company, setting up taxes, and managing accounts, there are numerous deadlines to track. Missing one can lead to fines or delays, so it is vital to understand what needs to be done and when.

This article breaks down every major deadline you will face in your first year, whether you are a sole trader or running a limited company. It covers registration dates, tax filing deadlines, PAYE and VAT obligations, and your first Companies House requirements.

First-year deadlines for sole traders

If you decide to operate as a sole trader, your reporting requirements are simpler, but there are still key dates you must meet.

Registering for Self Assessment

You must register with HMRC for Self Assessment by 5 October following the end of the tax year in which you started trading. The UK tax year runs from 6 April to 5 April.

For example, if you began trading in July 2024 (within the 2024/25 tax year), you must register by 5 October 2025.

Filing your first tax return

Your first Self Assessment tax return must be submitted by 31 January after the end of the tax year in which you started trading if filing online. Paper returns are due earlier, by 31 October.

The same 31 January deadline applies for payment of any income tax and National Insurance owed. If your tax bill exceeds £1,000, you may also need to make payments on account on 31 January and 31 July for the following year.

National Insurance contributions

Sole traders pay Class 2 and Class 4 National Insurance contributions. These are calculated as part of your Self Assessment, but it is worth checking your record through your HMRC account to ensure payments are up to date.

First-year deadlines for limited companies

Running a limited company involves more deadlines, as you will deal with both HMRC and Companies House. Each has its own filing requirements and penalties for missing them.

1. Corporation Tax registration

You must register your company for corporation tax within three months of starting to trade. Trading begins when you start carrying out business activities, not just when you register with Companies House.

HMRC will send your company a Unique Taxpayer Reference (UTR) shortly after incorporation. You need this to register for corporation tax online.

2. Accounting period and year-end

Your company’s first accounting period usually starts on the date of incorporation and lasts 12 months. Companies House automatically sets your year-end date as the last day of the month in which you incorporated.

For example, if you incorporated on 10 May 2024, your first accounting period ends on 31 May 2025. You can shorten or extend this later if needed, but for now, it determines your first filing deadlines.

3. Corporation Tax return and payment

Your first corporation tax return (CT600) is due 12 months after the end of your accounting period. However, payment of any corporation tax owed is due nine months and one day after the end of that period.

In the example above, if your year-end is 31 May 2025, you must pay corporation tax by 1 March 2026 and file your company tax return by 31 May 2026.

4. Annual accounts to Companies House

You must file your first set of company accounts with Companies House within 21 months of incorporation. This extended deadline only applies to the first year; in future years, accounts are due within nine months of the accounting year-end.

For instance, if your company was incorporated on 10 May 2024, your first accounts must reach Companies House by 10 February 2026.

5. Confirmation statement

Every company must file a confirmation statement (formerly the annual return) at least once every 12 months. The due date is typically the anniversary of your incorporation. You have 14 days after that date to submit it.

The confirmation statement confirms your registered office, directors, shareholders, and share capital. It must be filed even if no details have changed.

6. PAYE registration and deadlines

If your company plans to pay salaries, including your own as a director, you must register as an employer with HMRC before your first payday. PAYE submissions must be filed on or before each payday.

You must also pay PAYE tax and National Insurance to HMRC monthly, by the 22nd of the following month (or the 19th if paying by post). Quarterly payments are allowed for smaller employers with lower liabilities.

7. VAT registration

You must register for VAT once your business’s taxable turnover exceeds £90,000 in any rolling 12-month period. You can also register voluntarily earlier if it benefits your cash flow or professional image.

Once registered, you will need to submit VAT returns (usually quarterly) and pay any VAT owed within one month and seven days after the end of each VAT period.

8. Record keeping and bookkeeping

Although there are no fixed deadlines for bookkeeping, keeping accurate and timely records is crucial. HMRC requires businesses to maintain financial records for at least six years. Using accounting software makes it easier to track income, expenses, and taxes.

Common first-year filing timeline example

Let’s say you incorporated your company on 10 May 2024 and started trading immediately. Your key deadlines would look like this:

Corporation tax registration: by 10 August 2024 (three months after starting to trade)

First accounting year-end: 31 May 2025

Corporation tax payment due: 1 March 2026

Corporation tax return due: 31 May 2026

Annual accounts due to Companies House: 10 February 2026

Confirmation statement due: 10 May 2025 (with 14 days to file)

PAYE and VAT deadlines: Ongoing monthly or quarterly once registered

Understanding this timeline ensures you never miss a deadline and keeps your compliance on track from the start.

Penalties for missing deadlines

Both HMRC and Companies House impose fines for late submissions. For example:

Late company accounts can result in penalties starting from £150, increasing with further delays.

Late corporation tax returns attract an immediate £100 fine, plus additional daily penalties if delays continue.

Late VAT or PAYE payments can lead to interest and surcharges.

Failing to file a confirmation statement can lead to your company being struck off the register.

Keeping a calendar or using accounting software with automatic reminders helps prevent these issues.

Tips for managing deadlines effectively

Set reminders for each filing date in your digital calendar as soon as you register your business.

Use accounting software such as Xero or QuickBooks to automate tax and submission reminders.

Work with an accountant to manage tax registrations and filings, especially during your first year.

Keep digital copies of all receipts, invoices, and bank statements from day one.

Review your deadlines quarterly to ensure you remain on track as your business grows.

Conclusion

Your first year in business comes with a range of important deadlines for HMRC and Companies House. Sole traders must register for Self Assessment by 5 October and file tax returns by 31 January. Limited companies face additional obligations, including corporation tax registration, confirmation statements, and annual accounts.

By understanding and tracking these key dates, you can stay compliant, avoid penalties, and focus on building your business with confidence. Setting reminders, using software, and seeking professional support can make your first year far smoother and more successful.