Trust Ledger Accounting LtdNew Limited Company Deadlines: A First-Year Checklist
By Trust Ledger Accounting. Figures checked against GOV.UK and last updated on .
A new limited company has four first-year deadlines. It must tell HMRC within 3 months of starting to trade, file its first confirmation statement within 14 days of its first anniversary, and deliver its first accounts to Companies House within 21 months of incorporation. Corporation Tax is payable 9 months and 1 day after the end of the accounting period, and the Company Tax Return is due 12 months after it.
The deadlines at a glance
| What | Deadline | Sent to |
|---|---|---|
| Register for Corporation Tax | Within 3 months of starting to trade | HMRC |
| First confirmation statement | Within 14 days of the first anniversary of incorporation | Companies House |
| First accounts | 21 months after incorporation | Companies House |
| Pay Corporation Tax | 9 months and 1 day after the end of the accounting period | HMRC |
| Company Tax Return (CT600) | 12 months after the end of the accounting period | HMRC |
Sources: GOV.UK pages on running a limited company and a company's first accounts and Company Tax Return.
1. Tell HMRC within 3 months of starting to trade
Registering a company at Companies House does not finish the job with HMRC. Once the company starts doing business, you must register it for Corporation Tax within 3 months. Starting to do business includes buying, selling, advertising, renting a property or employing someone, so the clock often starts before the first sales invoice.
You register online using the company's Unique Taxpayer Reference (UTR), which HMRC posts to the registered office after incorporation. Registering late can lead to a penalty. Source: GOV.UK.
2. First confirmation statement: 14 days after the first anniversary
The confirmation statement confirms that the details Companies House holds are correct: the registered office, directors, shareholders, people with significant control and the company's business activity code. It is due at least once a year, and the first one must be filed within 14 days of the first anniversary of incorporation.
It is due even if nothing has changed and even if the company has not traded. A company that does not file can be struck off the register. Source: GOV.UK.
3. First accounts: 21 months after incorporation
A new company's first financial year normally ends on the last day of the month in which its first anniversary falls. That means the first accounts usually cover slightly more than 12 months. They must reach Companies House within 21 months of the date of incorporation.
From the second year onwards, accounts are due 9 months after the end of the financial year.
4. Corporation Tax: pay first, then file
Corporation Tax is due 9 months and 1 day after the end of the accounting period. The Company Tax Return (CT600) is due 12 months after the end of the accounting period. The payment deadline comes first, so in practice the return has to be worked out before the tax is paid.
Why a first year often needs two Corporation Tax returns
An accounting period for Corporation Tax cannot be longer than 12 months. When the first accounts cover more than 12 months, they are split into two periods, and each one needs its own Company Tax Return.
For example, a company incorporated on 15 May 2026 that trades from day one has a first financial year ending on 31 May 2027:
- First return: 15 May 2026 to 14 May 2027, the first 12 months
- Second return: 15 May 2027 to 31 May 2027, the remaining days
Each period has its own payment deadline, 9 months and 1 day after that period ends, so the tax for the first period in this example is due on 15 February 2028. The first accounts are due at Companies House on the same day, 21 months after incorporation. If the company did not trade straight away, its first Corporation Tax period starts when trading starts, and the dates move accordingly.
Other registrations to check
- VAT. You must register once taxable turnover goes over £90,000 in 12 months. See when to register for VAT.
- Payroll. If the company will pay a salary, including to a director, it normally needs to register as an employer with HMRC before the first payday.
- Self Assessment. Directors who take dividends or have other untaxed income may need to file their own return. See who needs to file a Self Assessment tax return.
What happens if a deadline is missed
Companies House charges an automatic penalty when accounts arrive late:
| How late | Penalty |
|---|---|
| Up to 1 month | £150 |
| 1 to 3 months | £375 |
| 3 to 6 months | £750 |
| More than 6 months | £1,500 |
Source: GOV.UK. A late Company Tax Return brings a separate HMRC penalty of £200 one day after the deadline and another £200 after 3 months. Source: GOV.UK. HMRC also charges interest on Corporation Tax paid late. The full tables are in our guide to late company accounts and CT600 penalties.
First-year checklist
- Note the incorporation date and work out the four deadlines above
- Keep the UTR letter from HMRC and the Companies House authentication code somewhere safe
- Register for Corporation Tax as soon as the company starts doing business
- Open a business bank account and keep company money separate from your own
- Keep every sales invoice and purchase receipt from day one
- Check whether you need to register for VAT or as an employer
- Put the confirmation statement date in your calendar
Our monthly packages for new companies start at £79 + VAT and include FreeAgent, the annual accounts, the Corporation Tax return and one director's Self Assessment. If you only need the year end done, we file company accounts and the CT600 together for £199 + VAT within 5 working days of receiving complete records.