How directors file a company tax return online

01 / THE DIRECTOR'S ROLE

Your responsibilities as a director

As a director, you are responsible for ensuring the company meets its filing duties, even if an agent or accountant prepares the figures. Where HMRC has issued and not withdrawn a notice to deliver a Company Tax Return, the company must file its CT600. Annual accounts are a separate Companies House obligation.

Keep adequate company records, check the figures and make sure filings and payments meet their deadlines. Late-filing penalties are charged to the company, not automatically to you personally. Persistent failures can, depending on the circumstances, also put the company at risk of strike-off and a director at risk of disqualification. See GOV.UK's guide to running a limited company.

For the wider legal requirements and how self-service compares with using an accountant, read the self-service Corporation Tax filing guide.

02 / FOUR DATES TO TRACK

Director's deadline calendar

These are separate obligations. The normal Corporation Tax payment deadline below assumes the company is not within the instalment-payment regime; confirm the dates for your company.

Example: For a period ending 31 March 2026, the normal tax payment date is 1 January 2027 and the CT600 filing date is 31 March 2027. If the accounts reference date is also 31 March 2026 and the ordinary nine-month accounts deadline applies, Companies House accounts are due by 31 December 2026.

For CT600 returns with a filing date on or after 1 April 2026, fixed late-filing penalties are £200 when late and a further £200 when more than three months late (£400 overall). After three successive late returns, these rise to £1,000 and a further £1,000 (£2,000 overall). Other HMRC penalties may apply. Companies House late-accounts penalties are separate: for a private company, they start at £150 for up to one month late and rise with the length of delay; they double if accounts are late two years in a row.

See the Corporation Tax deadlines and penalties guide for more detail.

Sources: GOV.UK Company Tax Returns, GOV.UK annual accounts, GOV.UK CT600 penalty increase, and GOV.UK Companies House late-accounts penalties.

03 / START WITH THE RECORDS

What to have ready

Gather the company UTR, your Corporation Tax-enrolled Government Gateway access, period dates, bookkeeping records and prior-year accounts. Have bank balances, asset transactions, director-loan records and dividend paperwork ready where relevant. If you will submit eligible accounts to Companies House, you will also need its authentication code.

Use the director's checklist to track your records and each separate deadline. Check which items apply to your company before you start.

04 / FROM FIGURES TO RETURN

How the WeFile wizard works, step by step

1. 1

   Company and period

   Find your company through the Companies House lookup and confirm the accounting period before entering figures.

2. 2

   Profit and loss

   Enter your sales and costs, or import bookkeeping figures from Xero, QuickBooks Online, FreeAgent or CSV. Review the imported figures.

3. 3

   Balance sheet

   Enter assets, liabilities and reserves. Check that the balance sheet reconciles with the profit and loss account and retained earnings before continuing.

4. 4

   Tax adjustments and capital allowances

   Add back disallowable costs and enter qualifying capital allowances. WeFile calculates Corporation Tax, including applicable Marginal Relief and associated-company limits, from the figures you provide.

5. 5

   Review accounts and computation

   Choose the applicable FRS 105 or supported FRS 102 accounts presentation. Review the generated accounts, iXBRL and PDF previews, and tax computation.

6. 6

   Submit and track

   Use your Corporation Tax-enrolled Government Gateway credentials for the CT600 Version 3 submission and, where applicable, your Companies House authentication code for accounts. Track each result separately; an IRmark is shown when HMRC supplies one.

WeFile calculates supported totals, retained earnings and tax from the information you enter. You supply and review the underlying figures: WeFile does not audit your bookkeeping or give tax advice. For help assessing the accounts regime and avoiding common mistakes, see the limited-company online tax return guide, including its FRS 105 checker.

05 / WHAT CHANGED

WeFile vs filing with HMRC's own online service

HMRC's free Company Tax Return service, often called CATO, closed on 31 March 2026. For normal online CT600 filing, companies now use commercial software. You still use your Corporation Tax-enrolled Government Gateway credentials: WeFile uses them to submit your return to HMRC.

Read what changed when HMRC's free CT600 service closed or compare routes in the former HMRC filing service alternative guide. WeFile appears on HMRC's Corporation Tax commercial software suppliers list; inclusion does not guarantee that an individual return will be accepted.

06 / FOLLOW BOTH RESULTS

After you submit

Treat sending the return and receiving its final status as distinct stages. Follow HMRC's reported result and, if you filed accounts, the separate Companies House result. An IRmark is displayed when HMRC supplies one. The CT600 submission and status guide explains what to check after sending.

If a submission is rejected, read the reported reason, correct the relevant figures or credentials and resubmit where appropriate. Acceptance is not guaranteed. If you discover an error after filing, a company can normally amend its CT600 within 12 months of the filing deadline; check the applicable amendment rules. Filing a return does not pay the tax—make the payment separately by its due date.