The free tool is gone
If you're reading this, you've probably just discovered that HMRC's free online CT600 filing tool closed on 31 March 2026. It's no longer an option — you need a plan.
Here's the short version: you now need commercial software or an accountant to file your Corporation Tax return.
The cheapest and simplest replacement is Taxpipe at £59 per return — no subscription, no hidden fees.
What exactly changed?
Until 31 March 2026, HMRC let you file a CT600 (Corporation Tax return) for free through their online portal. That portal has now been retired.
What did NOT change:
- You still need to file a CT600 ✅
- The deadline is still 12 months after your accounting period ends ✅
- The information required is the same ✅
- HMRC still processes returns the same way ✅
What DID change:
- You can't use HMRC's free tool anymore ❌
- You need to use commercial software that's recognised by HMRC ✅
- Your software must produce iXBRL accounts and computations ✅
Step-by-step: what to do right now
Step 1: Check your filing deadline
Your CT600 is due 12 months after your accounting period ends. For example:
- Year-end 31 March 2026 → file by 31 March 2027
- Year-end 31 December 2025 → file by 31 December 2026
Don't confuse this with the payment deadline — your Corporation Tax itself is due earlier, 9 months and 1 day after the period ends.
Missing the filing deadline is more expensive than it used to be. For filing dates on or after 1 April 2026, the automatic penalty is £200 the day you're late, plus another £200 at three months (it was £100/£100 for filing dates before 1 April 2026). At 6 and 12 months late, HMRC adds tax-geared penalties of 10% of the unpaid tax each time.
Step 2: Choose your replacement
For most small companies, the decision is simple:
| Option | Cost | Time | Best for |
|---|---|---|---|
| Taxpipe | £59 one-time | 15 minutes | Most small companies |
| Accountant | £300–£1,000/year | Days/weeks | Complex situations |
| Xero/Sage | £15–£50/month | Varies | Companies already using them |
Step 3: File your return
With Taxpipe:
- Sign up (free)
- Enter your company number — we pre-fill your details from Companies House
- Answer guided questions about your income and expenses
- We calculate your tax and generate all required documents
- Pay £59 and submit directly to HMRC using your own Government Gateway login
- Get confirmation once HMRC accepts your return
That's it. 15 minutes, start to finish. You'll need a Government Gateway account that's enrolled for Corporation Tax — the same login you'd have used for HMRC's old free service.
Frequently asked questions
Can I file a CT600 myself without an accountant?
Yes. If your company is straightforward (single director, UK income, no complex arrangements), software like Taxpipe makes it easy. You don't need accounting qualifications.
What about iXBRL accounts?
HMRC requires accounts in iXBRL format alongside your CT600. Taxpipe generates micro-entity (FRS 105) iXBRL accounts automatically — the standard most small companies use — along with the iXBRL tax computation, so you don't need to worry about it.
Is £59 the total cost?
Yes. No subscription, no monthly fees, no hidden charges. £59 covers your CT600 return, iXBRL micro-entity accounts, and direct HMRC submission.
What if my company is dormant?
It depends on whether HMRC has asked for a return. If you've told HMRC your company is dormant and they've confirmed it, no CT600 is due unless HMRC sends you a 'notice to deliver a Company Tax Return'. If you do receive a notice — common in the year you stopped trading — you must file even though there's nothing to tax. Taxpipe has a dormant company shortcut that pre-fills a nil return — it takes under 5 minutes.
When should I switch?
Now. The HMRC tool has already closed, so the next return you file will have to go through commercial software. Getting set up before deadline pressure hits makes everything smoother.
The bottom line
HMRC's free filing tool closing is a minor inconvenience, not a crisis. The replacement software is genuinely better — faster, smarter, and catches errors before you submit.
Sign up to Taxpipe for free, see your Corporation Tax calculated as you go, and pay the £59 only when you're ready to file.