HMRC’s free Company Tax Return service has closed: what to do now

HMRC’s free “File your accounts and Company Tax Return” service closed on 31 March 2026. If your company used it, you now need commercial software to file your Company Tax Return (CT600) with HMRC.

Last checked against GOV.UK on 29 September 2026.

A4O Accounts prepares the CT600 from your books and files it with HMRC. See the CT600 software, or get started free.

What was the service, and why has it closed?

For years, small companies with straightforward affairs could file their accounts and Company Tax Return with HMRC, and their accounts with Companies House, through one free online service. HMRC closed it on 31 March 2026. GOV.UK now says to use commercial software to file annual accounts and Company Tax Returns with HMRC.

The closure lines up with wider changes to company law. Companies House is also moving accounts to software-only filing, from April 2028. See our guide to that change.

What you need to file now

A Company Tax Return is more than the CT600 form. HMRC expects three things together:

• The CT600 return itself, plus any supplementary pages you need, such as CT600A for loans to participators.
• Your company’s accounts for the period.
• A tax computation showing how you got from accounting profit to taxable profit.

The accounts and computation have to be in iXBRL, a tagged format that HMRC’s systems can read. Filing software does the tagging for you.

Your deadlines haven’t moved

A late return gets an automatic £200 penalty, another £200 at three months, and after that HMRC can add a percentage of the unpaid tax. If your return is late three times in a row, the £200 penalties become £1,000 each. Companies House penalties run from £150 to £1,500, depending on how late the accounts are.

Choosing software

GOV.UK has a list of commercial software suppliers for Company Tax Returns. Being on it doesn’t mean HMRC recommends a product, so check a few things. There’s more in CT600 software: what to look for.

• Does it cover your whole return? The CT600 and any supplementary pages you need, the accounts and the computation, not just one part.
• Can it file your Companies House accounts too? Preparing both from the same figures saves typing them in twice, and keeps the two filings consistent.
• Where do the figures come from? Software that works from your bookkeeping means less re-keying at year end.
• Can you see what will be filed? Look for a preview of the tagged accounts and the return, box by box, before you submit.

If you filed through the old service last year

Have last year’s figures to hand: your balance sheet, any losses carried forward, and capital allowance pools. The first return you file through new software usually needs these as opening balances.

Moving to A4O Accounts

A4O Accounts prepares your accounts and CT600 from your books and files them with Companies House and HMRC. How to move across from HMRC’s service covers the steps, the cost and what isn’t supported.

More in this series: all the CT600 guides.