Miss a filing deadline as a UK company director and something unpleasant happens automatically — a penalty notice, mounting interest, or in the most serious cases the dissolution of your company without any further warning. The good news is that the calendar itself is not complicated: four recurring obligations, each with a fixed relationship to your accounting year-end.
The four key dates in your company's annual calendar
Before walking through each obligation, here is the complete picture for a company with a common 31 December year-end:
| Obligation | Deadline (for 31 Dec 2025 year-end) | Filed with | Consequence of missing |
|---|---|---|---|
| Confirmation statement | Within 14 days of review period end (annually) | Companies House | Company may be struck off the register |
| Annual accounts | 30 September 2026 (9 months after year-end) | Companies House | Automatic late-filing penalty; increases with delay |
| Corporation tax payment | 1 October 2026 (9 months and 1 day after year-end) | HMRC | Interest charged on unpaid amount from due date |
| CT600 return | 31 December 2026 (12 months after year-end) | HMRC | £100 initial penalty; further penalties for continued delay |
Understanding these four obligations is part of what it means to be a company director. For a full picture of the legal duties that come with directorship, see UK director responsibilities.
Confirmation statement: your annual snapshot of company information
The confirmation statement (which replaced the old annual return in 2016) is not a financial document — it does not contain your accounts or tax figures. It is a Companies House filing that confirms your company's registered information is accurate: the list of directors and their service addresses, the list of shareholders and the shares they hold, the company's registered office address, and its principal business activities.
You must file a confirmation statement at Companies House within 14 days of the end of each 12-month review period. The review period starts on the date of incorporation and rolls forward annually. If you incorporated on 15 March, your review period ends on 14 March each year and your confirmation statement is due by 28 March.
If you do not file, Companies House can begin striking-off proceedings — your company ceases to exist as a legal entity, and restoring a dissolved company is expensive and avoidable. The filing fee is modest; check GOV.UK for the latest amount.
Annual accounts: nine months, filed at Companies House
Every private limited company must prepare and file annual statutory accounts. These are the formal financial statements that capture the year's activity: the profit and loss account, the balance sheet, the cash flow statement (for larger companies), the directors' report, and accompanying notes.
The deadline for a private limited company is nine months after the end of its accounting reference period (year-end). A company with a 31 December year-end must file its accounts by 30 September of the following year.
Critically: these accounts are filed at Companies House — not with HMRC. They are also submitted alongside your CT600 to HMRC, but the statutory filing obligation is to Companies House, and it is Companies House that imposes late-filing penalties. Do not assume that submitting to HMRC covers the Companies House obligation.
Use the file your company accounts and tax return service on GOV.UK, which allows you to file both your accounts (to Companies House) and your CT600 (to HMRC) through a single submission. This joint filing route is the standard approach for most small companies.
Once filed, a version of your accounts becomes part of the public record at Companies House. Small companies — subject to meeting the current threshold criteria on GOV.UK — can file filleted accounts that omit the profit and loss statement from the public record, leaving only the balance sheet and notes visible to outside parties. This is the default choice for most early-stage companies who do not want competitors or customers to see their revenue and margins. We explore what these statements contain in detail in statutory accounts vs management accounts.
Nine months sounds generous until you add auditor availability in September. Book your accountant early — the filing rush is real.
First-year note: For newly incorporated companies whose first accounting period runs longer than twelve months (which is common when the company is set up part-way through the year), the first accounts deadline is calculated differently. Companies House extends the filing window for that first period. Your accountant or Companies House guidance will confirm the exact deadline based on your incorporation date.
Corporation tax: two separate deadlines for the same tax
Corporation tax sits on a different timetable from your accounts and involves two distinct acts: paying the tax and filing the return.
Paying corporation tax is due nine months and one day after the end of the accounting period. For a 31 December 2025 year-end, the tax payment is due by 1 October 2026 — one day after the accounts filing deadline. You need to have calculated your liability and transferred the funds to HMRC before that date, or interest begins to accrue.
Filing the CT600 (the corporation tax return) is due twelve months after the end of the accounting period. For a 31 December 2025 year-end, the CT600 must be filed with HMRC by 31 December 2026. This is the formal declaration of your taxable profits and how the tax liability was computed.
The gap between the payment deadline (month 9, day 1) and the filing deadline (month 12) means you are paying a provisional figure before you have submitted the formal computation. In practice, most companies have completed their accounts and know their tax liability well before the nine-month deadline — but managing cash flow to have the tax reserves ready is a practical discipline that founders should build into their budgeting from the start.
Our companion article UK corporation tax basics explains how taxable profit is calculated, what reliefs are available, and what the CT600 process involves in more detail. Current rates and thresholds are available at GOV.UK corporation tax.
What happens when you miss a deadline
Late filing has graded consequences:
Confirmation statement: No grace period. If you fail to file, Companies House will issue a warning and, ultimately, begin striking-off proceedings. The company can be restored but it is a costly and disruptive process.
Annual accounts at Companies House: An automatic civil penalty is levied the day after the deadline. The penalty amount increases based on how late the accounts arrive — the longer you wait, the larger the fine. Check GOV.UK for current penalty amounts, as these are set by Companies House.
Corporation tax payment: HMRC charges interest on the unpaid tax from the day after the due date. If the tax remains unpaid for a significant period, HMRC can also raise a formal surcharge. Interest is not tax-deductible for the company.
CT600 return: An initial flat penalty applies if the return is filed late, rising at three, six, and twelve months. HMRC can also issue a tax determination if no return is received.
Practical systems for staying ahead of the calendar
A few practices that work well for managing these dates:
Lock in your accounting year-end deliberately. Companies House assigns a default year-end twelve months from incorporation, but you can change it. Many founders align to 31 December or 31 March. Discuss with your accountant what works best for your model.
Set four calendar reminders after your year-end: 14 days (confirm the confirmation statement review period), eight months (prompt to finalise accounts with your accountant), nine months minus one week (accounts filing buffer), and eleven months (CT600 nearly due).
Maintain a corporation tax reserve account. From the moment you start generating profit, set aside an estimate of your corporation tax liability each month in a separate account. When the nine-month payment deadline arrives, the funds are already quarantined.
Use cloud accounting software throughout the year. A real-time ledger means accounts are largely ready to review before the filing window opens — your accountant should not be starting from scratch in September.
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Key takeaways
- A UK limited company has four annual filing obligations: confirmation statement, annual accounts at Companies House, corporation tax payment, and CT600 return to HMRC.
- Annual accounts must be filed at Companies House within nine months of your accounting year-end — not with HMRC.
- The corporation tax payment is due nine months and one day after year-end; the CT600 return itself is not due until twelve months — so you pay before you file.
- Missing any deadline triggers automatic penalties or, for the confirmation statement, the risk of company dissolution.
- Planning ahead — a tax reserve account, early accountant engagement, and fixed calendar reminders — removes almost all the risk from these obligations.
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