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HMRC CATO service closed 31 March 2026

HMRC's Company Accounts and Tax Online (CATO) free filing portal has now closed. Here's how you can file your Company Tax Return (CT600) and iXBRL accounts

From 1 April 2026, every company must file its Company Tax Return (CT600) and iXBRL accounts through commercial software — or a recognised filing agent like FinTags. No software to buy, no iXBRL to learn: just send your accounts and we take it from there.

Let FinTags file for me → Compare my options
✓ From £4 per page ✓ New & dormant companies from £30 ✓ Support till filing is accepted

What changed, and who it affects

If you searched "HMRC CATO closed", "file CT600 without CATO", or "company tax return online filing 2026" — here's the short version.

31 Mar 2026

HMRC's free Company Accounts and Tax Online (CATO) service closed to all new Company Tax Returns.

1 Apr 2026

All CT600s and iXBRL accounts must be filed through commercial software or a recognised agent.

Who's affected

Every company that used the free HMRC service — including small, micro, new and dormant companies.

Your two options from April 2026

Option 1 — Buy commercial software

  • ✕ Annual licence fees, whether you file once or many times
  • ✕ You learn iXBRL tagging and the HMRC taxonomy yourself
  • ✕ Rejections and amendments are yours to resolve
  • ✓ Suits accountants filing many returns in-house

Option 2 — Let FinTags file as your agent

  • ✓ Send accounts in Word, Excel or PDF — we do the rest
  • ✓ From £4 per page; new & dormant companies from £30
  • ✓ CT600 prepared and transmitted by an HMRC recognised agent
  • ✓ Unlimited revisions — support until HMRC accepts your filing
Get started with FinTags →

Switching from CATO takes three steps

No account to create, no software to install — here's exactly what happens when you switch to FinTags.

1

Send us your accounts

Word, Excel or PDF — exactly as you have them today

2

We tag and prepare

iXBRL tagging plus your CT600, ready for your review and approval

3

We file with HMRC

As your authorised agent — with amendments at no extra cost

First time using an agent?

Here's exactly what filing through FinTags looks like

If you've only ever used CATO, this will feel just as simple — you're not learning new software, you're just sending us a file.

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You don't need to reformat anythingSend your accounts exactly as you already have them — Word, Excel or PDF, same price either way.
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You don't need to learn iXBRLOur team tags every figure to the correct HMRC / Companies House taxonomy for you.
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You approve before anything is filedWe send the tagged accounts and CT600 back for your sign-off before we transmit anything to HMRC.
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If HMRC ever queries anything, it's on usUnlimited revisions, with a 100% acceptance guarantee, until your filing is accepted.
Frequently Asked Questions

Common questions about the CATO closure

HMRC's free Company Accounts and Tax Online (CATO) service closed to all new Company Tax Returns on 31 March 2026.

From 1 April 2026, you must file your CT600 and iXBRL accounts using commercial software or through a recognised agent such as FinTags.

HMRC is retiring its legacy free filing tools in favour of commercial software and agents that support current iXBRL and Making Tax Digital requirements more reliably.

Yes. File through HMRC-recognised commercial software, or send your accounts to a recognised agent like FinTags, who tags and files on your behalf.

Yes — FinTags is an HMRC recognised iXBRL solutions provider and files Company Tax Returns as an authorised agent.

Send your accounts in Word, Excel or PDF exactly as they are. FinTags tags them to iXBRL, prepares your CT600, and files with HMRC as your agent — no software or new login to set up.

FinTags charges from £4 per page for iXBRL tagging and £60 for CT600 filing, with new and dormant company packages from £30.

Switch from CATO today

Don't let the CATO closure delay your filing

Deadlines haven't changed — only the route. Tell us about your filing below and we'll come back with a firm quote and next steps within 60 minutes.

✓ No software to buy — send accounts in Word, Excel or PDF
✓ HMRC recognised agent — 100% acceptance guarantee
✓ From £4 per page · new & dormant companies from £30
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