# What is the corporation tax filing deadline?

Pick My Accountant (https://pickmyaccountant.co.uk/answers/corporation-tax-filing-deadline/): What is the corporation tax filing deadline? — Quick answer. UK limited companies must pay corporation tax within nine months and one day of their accounting period ending, and file the company tax return (CT600) within twelve months. Pick My Accountant reminds directors that statutory accounts are also due at Companies House nine months after the financial year end.

## Key facts

- Corporation tax payment: 9 months and 1 day after your accounting period ends
- Company tax return (CT600): 12 months after the period ends
- Statutory accounts to Companies House: 9 months after the financial year end
- Deadlines run from your company's own year end — there is no single national date
- Late CT600 filing starts at £100; late Companies House accounts start at £150

## What are the three corporation tax deadlines?

These are three different jobs, often three different systems. Missing the payment date costs interest even if the CT600 window is still open. Persistent late accounts can get a company struck off.

## Is there a single national corporation tax deadline?

That overlap is where an accountant earns the fee. Do not copy a neighbour’s January date onto your calendar unless you share a year end.

## What are the penalties for a late CT600 or late accounts?

File even if you cannot pay. Time to Pay is a conversation with HMRC; silence is a penalty. Dormant companies still have paperwork.

## Is corporation tax moving to Making Tax Digital?

Limited companies should still expect digital-first compliance in practice. VAT-registered companies already file VAT under MTD. Do not buy an MTD-for-CT product — it is not a thing.

## FAQs

**Q: Do dormant companies have to file?**
A: Yes. A dormant company still needs to file dormant accounts with Companies House each year, and must either file a CT600 or tell HMRC it is dormant so no return is required. Ignoring the paperwork leads to penalties even with no activity.

**Q: Can I file my own corporation tax return?**
A: HMRC's online service allows it, and very simple micro companies sometimes manage. But the payment deadline falls before the filing deadline, computations have strict rules, and mistakes are costly — most directors use an accountant.

**Q: What if my company made a loss?**
A: You still file the CT600 — losses can often be carried forward or back to reduce tax in other periods, but only if claimed through the return. The filing and Companies House deadlines apply whether or not tax is due.

Updated: 2026-08-13

Source: https://pickmyaccountant.co.uk/answers/corporation-tax-filing-deadline/