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File your CT600 and accounts in one place

DataTracks Nova is the smart way for micro-entities to prepare accounts and file with HMRC and Companies House,
without the complexity.

Filed through CATO before? Your first CT600 on Nova costs nothing, a limited introductory offer.

What CATO’s closure means for you

CATO (Company Accounts and Tax Online), HMRC’s free joint filing service, closed on 31 March 2026. If you used it, you no longer have a free route to HMRC, and your Corporation Tax return now has to go through commercial software.

Companies House is separate. Its own free WebFiling service is still open, and stays open until 31 March 2028. After that, software is mandatory there too.

DataTracks Nova does both. Your CT600 to HMRC now, and your accounts to Companies House whenever you need them, from the same set of figures.

If you filed through CATO, your first CT600 on Nova costs nothing.

What you get with Nova

Everything a micro-entity filing needs, in one place.

Micro-Entity
Accounts, Simplified

No accounting knowledge needed. Nova prepares your accounts.

Your CT600,
Made Easy

A guided platform walks you through every step.

One Preparation,
Two Filings

Enter numbers once, file with both HMRC and Companies House.

Smart Calculations
as You Go

Automatic and live Corporation Tax calculation, with clear guidance.

Mistakes Caught
Before Filing

Your return checked against HMRC and Companies House rules, with fixes flagged.

Auto-Fetch
Company Details

Company details pulled straight from the Companies House register.

Automatic iXBRL
Conversion

Converted instantly to HMRC-compliant iXBRL and filed with your CT600.

One Dashboard,
Full Visibility

Every filing tracked, from HMRC to Companies House.

Built to Grow
with You

Start with one company, add more as you grow, and invite colleagues in.

How Nova works

Find your company

Nova pulls your details from the Companies House register. If it is not there, you can type them in and carry on.

Fill in your numbers

Your Corporation Tax updates as you go, and Nova flags anything that looks wrong before you move on.

File from one place

Send your CT600 to HMRC, and your accounts to Companies House, from the same place.

Choose your plan

£25 per filing filed. Former CATO users get their first filing free.

Nova Ignite

£25 £0 first filing

Nova Core

£25 per filing

All prices exclude VAT. VAT is applied at 20% on the final purchase price.

Companies House filing is an add-on on either plan, £25 per filing, built in from day one, so there’s nothing extra to set up when the 2028 Companies House mandate applies to you.

Key dates and deadlines

12 months

File your CT600 with HMRC,
12 months from the end of your accounting period.

9 months

File your accounts with Companies House, 9 months from the end of your accounting period.

9 months, 1 day

Pay any Corporation Tax you owe to HMRC. Payment falls due before the return does.

31 March 2028

WebFiling closes. Every company must file with Companies House using commercial software.

File your CT600 late and the penalty starts at £200, doubled from £100 in April 2026, and rises the longer you leave it.

Trusted and recognised

HM Revenue
& Customs

DataTracks (DTracks Limited) is recognised by HMRC as an iXBRL Managed Tagging Service provider and as a commercial software supplier supporting Pillar 2 returns.

Companies
House

DataTracks (DTracks Limited) is recognised by Companies House as an authorised software provider for filing company accounts.

Featured blogs

October 2, 2026

Who Could Use CATO to File Their Returns with HMRC?

April 7, 2026

HMRC’s Free CT600 Filing Service Has Closed: What UK Companies Must Do Now

May 12, 2025

Micro-entity or small company? What the thresholds are now

Frequently Asked Questions

Why do I need software now?

HMRC’s free CATO service, Company Accounts and Tax Online, closed on 31 March 2026. From 1 April 2026 every company must file its Corporation Tax return using commercial software. Companies House is separate and is not affected until 2028.

Do I need to file with Companies House too, or just HMRC?

That depends on your company. You can file just your CT600 with HMRC, add Companies House filing as well, or do both from the same place. Nothing is forced on you either way.

Is Companies House filing mandatory right now?

No. Companies House still offers free filing through its own WebFiling service today. That closes on 31 March 2028, when software becomes mandatory there too. Filing through Nova now is optional, not required, until then.

What is iXBRL, and why does my filing need it?

iXBRL is the format HMRC requires for digital accounts and tax computations, a version of your accounts a computer can read as well as a person. Companies House will require it too from April 2028.

Does Nova generate my iXBRL accounts for me?

Yes. Nova converts your accounts into HMRC-compliant iXBRL automatically and files it alongside your CT600, with no separate conversion step.

What if Nova can't find my company when I try to connect it?

If your company details aren’t found in the Companies House register, you can enter them manually and continue. This doesn’t stop you from filing.

Is my first filing really free?

Yes, if you filed through CATO. Your first CT600 to HMRC costs nothing. It is an introductory offer. Everyone else, and every filing after your first, is £25 plus VAT. Filing your accounts with Companies House is £25 plus VAT either way, because CATO covered HMRC only.

How do I know if I was eligible for CATO?

CATO was for small UK companies filing for themselves, with no audit and straightforward tax affairs. The size test was turnover of no more than £632,000, a balance sheet total of no more than £316,000 and 10 employees or fewer. Note that these are the micro-entity thresholds as they stood before April 2025, when they rose to £1 million and £500,000. Nova checks your company against CATO’s rules when you sign up, so you do not have to work it out yourself.

Can accountants use Nova?

Yes. CATO was built for companies filing for themselves, not for agents acting on a client’s behalf, so it was never a route accountants could use in their own right. Nova Core is, at £25 plus VAT per filing, with team access, one dashboard for every client and volume discounts.

Do your prices include VAT?

No. All prices exclude VAT. VAT is applied at 20% on the final purchase price.

Is there a discount for filing many filings?

Yes, on Nova Core. Volume discounts are available for accountants and firms filing a high number of entities. Call +44 20 4514 5352 or write to enquiry@datatracks.co.uk to discuss your volume.

Is my data secure?

Yes. DataTracks holds ISO 27001 and ISO 9001 certification and is independently audited to SOC 2 Type II.

Stellar Product, Interstellar Possibilities

Ready to find out what Nova can do for you?