Can you still file a CT600 for free?

Since HMRC’s free service closed on 31 March 2026, every Company Tax Return goes through commercial software. Some of it costs nothing to file with, some is free only with a particular bank account, and some lets you prepare a return free but charges to send it. Here’s how to tell the difference before you start.

Last checked against GOV.UK on 25 October 2026.

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

The government option has gone

HMRC’s “File your accounts and Company Tax Return” service closed on 31 March 2026. GOV.UK now says to use commercial software to file Company Tax Returns. There’s no replacement government service for the CT600. See what to do now the service has closed.

GOV.UK keeps a list of the commercial software you can file with. It doesn’t say which products are free, so you have to check each one.

Five kinds of “free”

We checked FreeAgent and TinyTax on their own pages on 25 October 2026, and the others on 1 October 2026 for our comparisons. Prices change, so check again before you choose.

Free with a bank account

FreeAgent says it’s free for limited companies with a NatWest, Royal Bank of Scotland or Ulster Bank business account “for as long as you retain the account”. With Mettle, you have to make at least one transaction a month from the Mettle account, or FreeAgent’s fees apply. FreeAgent says the free accounts have the same features as paid ones, and that its CT600 “is supported for most micro-entities”.

If you already bank with one of them, it’s worth a look. If you’d be switching banks to get it, count that as part of the cost.

Free to prepare, pay to file

Some products let you build the whole return free and only ask for payment at the end. That’s a fair way to try software, but it isn’t free filing. TinyTax’s pricing page says so plainly: “You can prepare your CT600 and preview your accounts for free, but filing requires a subscription.”

What the free version should include

A free product only helps if it produces the whole return. HMRC expects three things together:

• The CT600, and any supplementary pages you need, such as CT600A for a director’s loan
• The company’s accounts for the period, in iXBRL
• The tax computation, in iXBRL

Then check:

• Is filing itself free, or only preparing? Look for the price on the submit step, not the sign-up page.
• Do you need a card to start? A card at sign-up usually means a trial.
• Does it file your Companies House accounts too? If not, you’ll be entering the same figures twice.
• What happens if prices change? Look for how much notice you’d get.

More on all of this in CT600 software: what to look for.

Companies House accounts are still free to file

Companies House doesn’t charge to file annual accounts, and its own online service still takes micro-entity, small, abridged and dormant accounts. That ends in April 2028, when accounts move to software-only filing in iXBRL. See software-only accounts filing from April 2028.

So the Companies House side can still be free without any software. The CT600 is the part that now needs it.

A4O Accounts

A4O Accounts is ours. It’s free to get started, including filing, and you don’t need a card. If we ever introduce paid plans, we’ll tell you at least 30 days before anything changes. It prepares your accounts, computation and CT600 from your books, in iXBRL, and files the return with HMRC and the accounts with Companies House. CT600A and CT600L are supported; other supplementary pages and group accounts aren’t yet. See free CT600 software and how other CT600 software compares.

More in this series: all the CT600 guides.