How to File a CT600 for a Dormant Company (Step-by-Step)

How to File a CT600 for a Dormant Company

Your company hasn't traded. No income, no expenses, no activity. But you still need to file a CT600 — and you can be fined if you don't.

Do Dormant Companies Really Need to File?

Yes. If HMRC has issued a CT603 (notice to deliver a Company Tax Return), you must file — even if the return shows all zeros.

The only exception: if you've told HMRC your company is dormant AND they've confirmed they won't issue CT603 notices. But most directors never do this, so you still get the notice.

What Goes on a Dormant CT600?

A dormant CT600 is straightforward:

• Box 1: Company name
• Box 2: Company registration number
• Box 3: Tax reference (UTR)
• Box 4: Company type — enter 0 for an ordinary dormant limited company (the numbered codes apply only to special entity types such as unit trusts, investment companies, charities and CASCs)
• Boxes 30–35: Accounting period dates
• Box 80: Tick to confirm accounts and computations are attached for this period
• Box 145: Turnover = £0
• Box 315: Total profits = £0
• Box 525: Tax payable = £0
• Boxes 975–985: Declaration — the declarant's name, date signed, and status (e.g. Director)

There is no dormancy tick-box on the CT600. Dormancy is indicated simply by entering zero figures throughout — the form shows HMRC that nothing taxable happened in the period.

Everything else: zero or blank.

How to File with Taxpipe

Taxpipe auto-detects dormant companies and takes a shortcut:

1. Sign up at taxpipe.co.uk/signup
2. Enter your company number — we fetch your details from Companies House
3. Enter your Government Gateway user ID and password — required to file with HMRC
4. Select "Dormant" in the wizard — all boxes auto-zero
5. Review — takes 30 seconds
6. Pay £59 and submit

Your return is filed directly to HMRC. You'll get a confirmation with a correlation ID.

What About Accounts?

Dormant companies also need to file accounts at Companies House, but these are even simpler. You can file dormant accounts for free at Companies House. This is separate from the CT600.

What If My Company Has a Bank Account?

Having a bank account doesn't automatically make your company non-dormant. A company is dormant if it has had no significant accounting transactions during the period.

Significant transactions include:

• Any trading income or expenses
• Paying dividends
• Buying/selling assets
• Receiving interest (other than a tiny amount on the bank account)

Transactions that DON'T count:

• Filing fees paid to Companies House
• Late filing penalties
• Bank interest under a few pounds (practice varies)

Can I Make My Company Dormant?

If your company has stopped trading:

1. File final accounts at Companies House
2. File final CT600 covering the trading period
3. Write to HMRC saying the company is now dormant
4. HMRC should stop issuing CT603 notices

If you plan to trade again in future, keep the company dormant rather than dissolving it.

What If I'm Late?

Same penalties as any other CT600 — and they apply even when the tax bill is £0, because the penalties are for late filing, not late payment.

Filing dates before 1 April 2026:

• £100 immediately (day 1)
• A further £100 at 3 months
• At 6 months: 10% of any unpaid tax (£0 for dormant companies)
• At 12 months: a further 10% of any unpaid tax (£0 for dormant companies)

Filing dates on or after 1 April 2026:

• £200 immediately (day 1)
• A further £200 at 3 months
• The 6- and 12-month tax-geared penalties remain the same percentage
• A third consecutive late return triggers £1,000 in fixed penalties

For dormant companies, the tax-geared penalties at 6 and 12 months are £0 (there is no unpaid tax). The fixed penalties still apply.

File your dormant CT600 now →

Taxpipe — Dormant company? File in 5 minutes. £59.