HMRC tax filing service closure – how it affects Corporation Tax payers

From 1 April 2026, HMRC is closing its free online service for filing the CT600 form. That means no more logging into HMRC’s website to submit your Corporation Tax return. Instead, you’ll need to file using HMRC approved accounting software.

Before panic sets in, let’s walk through what’s changing and what it means for you.

In this article we’ll cover:

• What’s happening to the HMRC free filing service
• What the CT600 form actually is
• Who this change affects
• How Corporation Tax filing will work from April 2026
• What to look for in HMRC approved accounting software
• How ANNA can help with Corporation Tax filing

What’s changing with Corporation Tax filing

Right now, lots of small companies file their Corporation Tax return directly through HMRC’s own online service. From 1 April 2026, that option disappears. HMRC is closing its service that allows CT600 form submissions free through its website.

HMRC’s aim is to modernise its systems and move everything onto software-based filing. The result is that filing through HMRC’s website simply won’t be an option anymore.

A quick refresher on the CT600 form

The CT600 form is the form your company uses to report its Corporation Tax to HMRC. It includes:

• Your company’s profits or losses
• The Corporation Tax you owe
• Any reliefs or allowances you’re claiming

Most companies file a CT600 form once a year, alongside their company accounts and computations. Even if your company made no profit, you still usually need to file one. This change does not remove the requirement to file. It just changes how you do it.

Who does this affect?

If you run a UK limited company and file your own Corporation Tax return, this closure applies to you.

It doesn’t matter if:

• Your company is small
• You only trade part time
• You usually have nothing to pay

If you need to submit a CT600 form after 1 April 2026, you’ll need to do it through HMRC approved software.

If an accountant already files your Corporation Tax for you, they’ll likely already be using software, so this change may barely register. If you file yourself, it’s a bigger shift.

How Corporation Tax filing will work from April 2026

From April 2026 onwards, the process looks like this:

• Prepare your company accounts
• Complete your Corporation Tax return
• Submit the CT600 form using approved software
• Pay any Corporation Tax due

You won’t log into HMRC to upload the return anymore. Instead, the software sends everything securely to HMRC on your behalf.

The good news is that most software will guide you through the process step by step, flagging errors before you submit and saving your info for next time.

What to look for in HMRC approved accounting software

Not all software is created equal, so it’s worth choosing something that suits how you run your business.

When looking at HMRC approved accounting software, it’s worth checking:

• It supports CT600 form filing
• It’s easy to use without accounting jargon
• It works for companies without an accountant
• It clearly shows what you owe and when
• It keeps records in one place

This is exactly where tools built for small businesses can make a big difference.

How ANNA provides an alternative

ANNA is HMRC approved accounting software, which means thousands of our customers are already using it to file their CT600 form online. And many don’t have to do anything at all because ANNA’s AI-powered Auto Accountant does it for you.

ANNA’s Corporation Tax tools are designed for directors who want things explained clearly and done properly, without needing to become a tax expert. With ANNA, you can:

• Automatically prepare and submit your CT600 form directly to HMRC using transaction data and uploaded documents
• See what Corporation Tax you owe and when it’s due
• Keep your accounts and records in one place
• Get guided prompts that help you avoid common mistakes
• File even if you don’t have an accountant

For Corporation Tax, Auto Accountant now handles 90 percent of filings without any human intervention. It continuously updates tax estimates throughout the year, giving customers real-time visibility into their financial position, supporting better cash flow planning and reducing unexpected liabilities.

Why it’s worth thinking about this now

April might seem far away, but deadlines have a habit of creeping up. Getting familiar with Corporation Tax filing using software now means:

• No last minute stress
• Fewer surprises when HMRC switches the service off
• More confidence that your CT600 form is done right

It also gives you time to choose HMRC approved accounting software that actually fits your business, rather than grabbing whatever seems quickest on deadline day.

The bottom line

HMRC closing its free online CT600 filing service is a big change, but it doesn’t have to be a scary one. Corporation Tax filing is still very much a thing, it’s just moving into software-only territory.

With HMRC approved accounting software like ANNA, filing your CT600 form can be simpler, clearer, and far less painful than you might expect.

And anything that makes tax feel a bit less taxing is usually a win.