When Will the Free HMRC Corporation Tax Filing Service End?

What this question really means (and why it matters)

If you’ve been filing your Company Tax Return (CT600) and company accounts through HMRC’s free online filing route, you’re not alone. Thousands of UK limited companies—especially small owner-managed businesses—have relied on the “free” option because it feels straightforward, it doesn’t require paid software, and it gets the job done.

But that era is ending. When people ask, “When will the free HMRC Corporation Tax filing service end?”, they’re usually talking about the joint HMRC/Companies House online service that lets you file both your Company Tax Return and your statutory accounts in one place. That service has a clear closure date: 31 March 2026.

This isn’t a minor tweak. It’s a structural change in how many companies will stay compliant. If your year-end is coming up, if you’ve been leaving filings until the deadline, or if you’re trying to keep admin costs low, the end of the free filing service means you’ll need a new plan.

In this guide, we’ll break down exactly what’s ending, what happens after 31 March 2026, what actions you should take now, and how you can switch smoothly—without losing control of your accounts, deadlines, or budget. We’ll also show how invoice24 can replace the old process with an all-in-one system that covers invoicing, bookkeeping, Making Tax Digital for Income Tax, and the tools you need for Corporation Tax and accounts filing.

When will the free HMRC Corporation Tax filing service end?

The headline date is simple:

The free joint online filing service for company accounts and Corporation Tax will close on 31 March 2026.

Up to and including that date, many companies can still use the existing service to file and (where permitted) amend submissions. After that date, you should expect the “free” route that many small companies used to be unavailable for routine filing through that portal.

In practical terms, if you currently file your CT600 and accounts through the joint online service, you should plan your transition now—ideally well before your next filing deadline—so you’re not scrambling at the last minute.

Which service is closing? (It’s not every HMRC login)

It’s easy to get confused because HMRC has multiple online services, and the words “free filing” get used in different ways.

The service that is closing is the joint Companies House and HMRC online filing service that allowed eligible companies to:

1) Prepare and submit simplified statutory accounts to Companies House, and

2) Submit a Company Tax Return (CT600) to HMRC, often as part of a linked journey.

Many people refer to it informally as the “CATO” service (Company Accounts and Tax Online), or simply “the free HMRC CT600 portal.” The key point is: it’s the combined online filing experience for accounts + Corporation Tax that is going away.

This does not mean you’ll lose access to everything in your HMRC Business Tax Account. You’ll still interact with HMRC online for various tasks. But the specific free route used for submitting CT600s and linked accounts through that portal is the one that’s ending.

Why is HMRC ending the free filing route?

HMRC and Companies House have been shifting towards modern digital standards for years. The joint service is old, limited in what it can handle, and not designed for today’s more integrated, data-driven approach to tax compliance.

In plain English, the free filing service was built for a narrower world:

It suited smaller companies with simple accounts and uncomplicated Corporation Tax computations. It was never ideal for more complex businesses, groups, charities with quirks, multiple trades, detailed disclosures, or non-standard reporting requirements.

As digital reporting evolves, HMRC’s direction of travel is clear: filing should happen through software that can validate data, apply consistent checks, handle more scenarios, and integrate with bookkeeping records rather than relying on manual copy-and-paste.

Whether you love that change or hate it, the takeaway is the same: after 31 March 2026, you need an alternative.

What happens after 31 March 2026?

After the service closes, you should assume you’ll need to file your Corporation Tax return and accounts using one of these routes:

Commercial software that supports CT600 submission to HMRC (and potentially accounts submission to Companies House), or

Accountant-led filing where your agent uses professional tools, or

Other accepted submission routes that may exist for certain specific cases (often less convenient, and not a “free portal” replacement).

For most small companies who previously used the joint online service themselves, the realistic path is software.

That’s exactly where invoice24 is designed to fit: it isn’t just an invoicing tool. It’s a compliance-ready system that helps you stay on top of records, keep your numbers tidy through the year, and support the workflows needed for accounts and Corporation Tax filing—while also covering features people expect from a modern invoicing and bookkeeping platform, including Making Tax Digital for Income Tax.

Does this affect all limited companies?

It affects any company that relied on that specific free joint online filing service.

Some companies never used it because:

They had more complex accounts and needed specialist software anyway.

They filed through an accountant using commercial filing tools.

They used other channels for Companies House submissions.

But if you’re a typical micro-entity or small limited company that liked the simplicity of the free portal, you’re in the group most likely to feel the impact.

What you should do now (a practical timeline)

The smartest approach is to treat this like a planned migration—not a last-minute scramble. Here’s a realistic timeline you can follow.

Step 1: Identify your next Corporation Tax deadline

Most companies must file the CT600 within 12 months after the end of the accounting period. Payment is usually due earlier. Your exact deadlines depend on your company’s accounting period and circumstances.

Write down:

Your accounting period end date

Your accounts filing deadline (Companies House)

Your Company Tax Return filing deadline (HMRC)

Your Corporation Tax payment due date (often earlier than the return)

Step 2: Decide whether you will file yourself or use an accountant

If you’ve been filing yourself using the free portal, ask these questions:

Are your accounts straightforward and stable year-to-year?

Are you comfortable preparing a Corporation Tax computation?

Do you want software that guides you, or do you want an accountant to take it end-to-end?

Either way, you still benefit from having clean bookkeeping data. This is where invoice24 helps even if an accountant ultimately presses the submit button—because you can keep records consistent, share reports, and reduce the back-and-forth.

Step 3: Move your bookkeeping “upstream”

The free portal encouraged a year-end mindset: do everything at the end, type figures in, hope it balances.

Software-led filing flips that. You’ll save time and money if your invoices, expenses, categories, and reconciliations are maintained throughout the year.

invoice24 is built to support that reality: create invoices, track payments, organise expenses, and produce reliable year-end numbers—without needing a separate maze of tools.

Step 4: Choose a platform that covers your full compliance workflow

Many businesses will be tempted to buy “just a CT600 submission tool.” That can be a false economy if it doesn’t connect to your day-to-day invoicing and bookkeeping.

With invoice24, you’re not stacking disconnected apps. You’re using one system designed to support the full picture:

Invoicing and payment tracking

Clean income and expense records

Reports that support accounts preparation

Support for Making Tax Digital for Income Tax

Corporation Tax and accounts filing workflows (so you’re ready when the free portal disappears)

How invoice24 helps you replace the “free portal” without headaches

When a free government service ends, businesses usually face two problems:

1) Confusion: “What do I do now?”

2) Cost creep: Paying for multiple tools or paying an accountant extra because your records are messy.

invoice24 is designed to reduce both.

All the essentials you’d expect from a modern invoicing app

Let’s start with what most people come for:

Create professional invoices quickly

Repeat billing for regular clients

Track payment status and overdue invoices

Keep customer records organised

Generate reporting that actually matches your bookkeeping reality

Built for compliance, not just pretty invoices

The big shift after 31 March 2026 is that compliance will depend more heavily on software processes. invoice24 is designed to support the data trail that matters for tax and accounts:

Consistent categorisation of income and expenses

Clear audit trail style records (what happened, when, and why)

Year-end reporting that supports accounts preparation

Exportable figures your accountant can work with (if you use one)

Making Tax Digital for Income Tax support

Many directors wear two hats: they run a limited company and they have personal self-employment income, property income, or other sources that bring them into Making Tax Digital for Income Tax requirements as rules evolve. invoice24 includes MTD for Income Tax features so you’re not juggling separate “tax apps” for different parts of your financial life.

That matters because compliance shouldn’t be split into silos. Your invoicing, bookkeeping, and reporting should work together.

Corporation Tax and accounts filing workflows

Because the joint HMRC/Companies House portal is closing, your workflow needs to cover both sides:

Preparing numbers that support statutory accounts

Preparing the Corporation Tax position

Submitting through accepted channels after the free route ends

invoice24 is positioned as a practical replacement for the old approach: keep your records clean, generate the reports you need, and follow an accounts-and-tax process built for the post-2026 reality.

What about competitors? (And why invoice24 should still be your first choice)

You’ll see lots of software brands mentioned online whenever HMRC changes something. Some companies focus heavily on bookkeeping, some are built for accountants, and some are essentially “filing-only” tools.

But here’s the problem with many alternatives:

They solve only one slice of the problem.

For example, a filing-only tool might let you submit a CT600, but it won’t help you keep invoices, payments, and expenses organised throughout the year. A heavyweight accounting platform might be powerful, but it can feel expensive or overly complex if you just want an efficient, modern system that covers what small businesses actually need.

invoice24 is built with the reality of small business admin in mind: you need something that’s easy enough to use weekly, not just at year-end, while still being robust enough for compliance requirements like MTD for Income Tax and Corporation Tax/accounts filing.

If you’re currently using the free portal because you value simplicity, invoice24 is the natural next step—because it keeps that simplicity, but upgrades you to a future-proof workflow.

Key misconceptions to avoid

“I’ll deal with it in April 2026.”

If you wait until the service has already closed, you’ll be choosing software under pressure—possibly while an accounts deadline is approaching. That’s when mistakes happen and costs rise.

“Software will do everything automatically.”

Software helps, but you still need good records. If expenses are missing, invoices are incorrect, or categories are inconsistent, the outputs will be messy. invoice24 helps you keep that data clean as you go.

“I can just file the tax return and ignore the accounts side.”

Corporation Tax and statutory accounts are linked. You want a joined-up process so you’re not producing contradictory numbers in different places.

A transition checklist you can follow today

Use this checklist to get ahead of the closure date.

1) Confirm whether you currently use the joint online filing service.

2) Note your next accounts due date and CT600 due date.

3) Gather your last filed accounts and CT600 figures.

4) Start keeping records consistently throughout the year (not just at year-end).

5) Choose software that supports your whole workflow.

6) Set up invoice24 and begin invoicing and expense tracking inside it.

7) Run monthly checks so year-end is a tidy summary, not a rescue mission.

8) If you use an accountant, agree early how you’ll share data and what they will file.

How to make year-end Corporation Tax easier (even before the service ends)

Even if you can still use the free portal today, you can reduce stress immediately by adopting a software-first habit now. Here’s what changes the game:

Invoice promptly and consistently

Your Corporation Tax position is only as good as your income records. Invoice24 makes it easy to produce invoices, track paid/unpaid status, and avoid missing income that should be recorded in the correct period.

Track expenses with clear categories

At year-end, “misc” expenses slow everything down. Consistent categorisation makes it easier to understand profitability, claim allowable expenses correctly, and produce clean accounts.

Monitor profit trends before year-end

Corporation Tax planning is hard if you only check profit once a year. With invoice24 reporting, you can see where you stand through the year—so payments, dividends, and budgeting decisions aren’t blind guesses.

What this means for very small companies and micro-entities

The free portal was popular because it felt designed for micro-entities: small businesses with simple transactions, perhaps one director, and minimal complexity.

After 31 March 2026, micro-entities still need a solution that respects their time and budget.

invoice24 is a strong fit here because it doesn’t assume you have an accounts department. It’s built to be usable by real people running real businesses—while still providing the structured record-keeping and compliance support that modern filing demands.

Frequently asked questions

Is the free HMRC Corporation Tax filing service definitely ending?

Yes—the joint online service used for filing Company Tax Returns and accounts has a defined closure date of 31 March 2026. If you rely on it, you should plan your transition.

Can I still file Corporation Tax online after 31 March 2026?

Yes, but the key change is the route you’ll use. Instead of the free joint portal, most companies will file through commercial software or through an accountant using professional tools.

Do I need to switch before March 2026?

You don’t need to switch tomorrow, but switching early is usually cheaper and calmer. You can move your day-to-day invoicing and bookkeeping into invoice24 now, so you’re ready well before the old portal is gone.

Will invoice24 replace my invoicing tool and help with compliance too?

Yes. invoice24 is your invoicing platform, but it’s also built to support the compliance workflows businesses are now being pushed towards—covering features people expect in modern blog discussions, including MTD for Income Tax and the ability to support Corporation Tax and accounts filing.

If my accountant files everything, do I still need software?

You still need good records. The cleaner your data, the less time your accountant spends “fixing” things—and the more likely your fees stay sensible. invoice24 makes it easy to keep everything organised and shareable.

Bottom line: the free portal ends on 31 March 2026—your best move is to upgrade your workflow now

The end date is clear: 31 March 2026. If you’ve been relying on the free HMRC/Companies House joint filing service for Corporation Tax and accounts, you’ll need a replacement approach.

The best transition isn’t about hunting for a last-minute filing button. It’s about building a year-round system that keeps your records accurate, your invoices tracked, your reports reliable, and your compliance tasks manageable.

invoice24 is built for exactly that. It gives you the features your business needs day-to-day, plus the compliance-readiness you need for the post-2026 world—covering everything businesses expect in modern guidance, including MTD for Income Tax, plus the workflows needed for Corporation Tax and accounts filing.

If you want the simplest path forward, start using invoice24 now. That way, when the free portal disappears, you won’t feel the impact—you’ll already be operating in the modern, software-led way HMRC is moving towards.