Overview
A company that becomes active normally needs to tell HMRC, calculate taxable profits, pay the tax and file a Company Tax Return. Accounting profit is adjusted for tax rules, so it is not always the same as taxable profit. The return deadline is later than the usual payment deadline.
Who this applies to
UK companies and certain clubs, associations and unincorporated bodies within Corporation Tax.
Key points
- The main rate is 25% and the small profits rate is 19%, with marginal relief potentially applying between the thresholds.
- Associated companies and short accounting periods can reduce the profit thresholds.
- Losses, capital allowances and reliefs require supporting records.
- From 1 April 2026, companies that used the old joint HMRC filing service need appropriate commercial software or another permitted route.
Important dates and deadlines
Corporation Tax is usually due 9 months and 1 day after the accounting period ends for companies outside instalment-payment rules. The Company Tax Return is normally due 12 months after the end of the accounting period.
Practical checklist
- Confirm the accounting period.
- Reconcile accounts to taxable profit.
- Review fixed assets, loans, dividends and connected parties.
- Pay using the correct 17-character reference.
- File the return and retain submission evidence.
Frequently asked questions
Why is the tax due before the return?
The normal payment date is 9 months and 1 day after the period, while the return is due 12 months after it.
Is Corporation Tax always 25%?
No. The small profits rate and marginal relief may apply, subject to thresholds and associated-company rules.
How Accountants4All can help
Support matched to your circumstances
Accountants4All prepares the tax computation, confirms the payment reference and deadline, files the return and records the submission in the portal.
Official sources and further reading
This page is general guidance and does not create an adviser/client relationship. Tax rules and official guidance can change. Use the official sources above and obtain advice based on your circumstances.
Read the full tax disclaimer