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Do I owe a CT600?

Seven short questions about your company's activity and HMRC status. We'll tell you whether you owe a nil CT600, a full CT600, or no return at all — and what to do next.

  1. 1.Did the company receive any money during the accounting period?

    Sales, fees, bank interest, dividends, rent — anything coming in.

  2. 2.Did the company pay any expenses from its own account?

    Subscriptions, accountancy fees, software, anything spent through the company.

  3. 3.Is the company currently registered for VAT?

    If you're not sure, check your HMRC account or your last VAT certificate.

  4. 4.Is the company registered as an employer (PAYE)?

    Paying anyone — including yourself — a salary normally requires PAYE registration.

  5. 5.Has HMRC sent you a notice to deliver a Company Tax Return (CT603) for this period?

    Look for a letter or email titled 'Notice to deliver a Company Tax Return'.

  6. 6.Has HMRC previously confirmed the company is dormant for Corporation Tax?

    A written confirmation from HMRC, or notice that no further CT600s are required.

  7. 7.Is the CT600 filing deadline for this period already past?

    The filing deadline is 12 months after the end of the accounting period.

Why "do I owe a CT600?" is the wrong question for most directors

The question most directors ask is: do I owe a CT600? The real question is: has HMRC issued a notice for this period, and have they confirmed the company is dormant for Corporation Tax? Those two answers determine everything.

The default position

HMRC sets up a Corporation Tax record for every new limited company. From that moment on, you have a CT600 obligation for every accounting period unless and until HMRC formally confirms the company is dormant for CT purposes. Filing dormant accounts with Companies House does not satisfy this. Companies House and HMRC are separate regulators with separate records.

The three outcomes

  • You owe a nil CT600. The most common outcome for dormant companies. Read how to file a nil CT600 for the steps.
  • You owe a full (non-nil) CT600. If the company has had income, expenses, or is registered for VAT or PAYE, HMRC considers it trading. Engage an accountant.
  • You owe nothing for this period. Only if HMRC has formally confirmed dormant CT status and has not issued a notice for the period.

If you're already overdue

The longer you leave it, the more penalties stack up — £100 + £200 fixed, plus up to £900 in daily penalties per missed period. The right move is to file the missing return immediately. See late filing penalties for dormant companies for the full breakdown, or HMRC penalty letters explained if you're trying to decode the specific letter you've received.

This tool is a guide, not legal advice

The check above covers standard dormant-company scenarios. If your situation is unusual — group structures, holding companies, restored companies, or you're disputing an HMRC assessment — talk to an accountant. For the full background, read our complete guide to filing a CT600 for a dormant company.

Need to file a nil CT600?

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