Corporation Tax Return Filing Deadline

30th September 2025 – For accounting period ending 30th September 2024

If your company’s accounting period ended on 30th September 2024, your Corporation Tax return (CT600) must be filed with HMRC by 30th September 2025.

📌 Key Points

• Filing deadline: The Corporation Tax return must be submitted 12 months after the end of your accounting period.

• Payment deadline: Corporation Tax itself is due 9 months and 1 day after your year end (in this case, 1st July 2025). This means payment is due before the filing deadline.

• The return must include your company’s financial details, tax calculations, and supporting documents such as statutory accounts and computations.

⚠️ What Happens if You Miss the Deadline

• HMRC will issue an automatic late filing penalty:

  • £100 if the return is up to 3 months late.

  • £200 if more than 3 months late.

  • Further penalties if over 6 or 12 months late (including a percentage of unpaid tax).

• Persistent late filing can lead to increased penalties and HMRC scrutiny.

✅ How JDH Accounting Solutions Can Help

At JDH Accounting Solutions, we make sure your Corporation Tax returns are prepared and submitted correctly and on time. We will:

• Calculate your Corporation Tax liability accurately.

• Prepare your CT600 return with the necessary supporting documents.

• File your return electronically with HMRC.

• Identify tax reliefs and allowances to minimise your bill.

• Remind you of deadlines so you stay compliant and avoid penalties.

By working with us, you can focus on running your business while we ensure your Corporation Tax obligations are fully met.