With HMRC's free filing tool closing in March 2026, every UK company director needs an alternative. Here's an honest look at your options — what each one costs, what it does well, and where it falls short.
Why you need CT600 software now
HMRC has announced that their free online filing service for Corporation Tax returns will close on 31 March 2026. After that date, you'll need to use commercial software or an accountant to file your CT600.
This affects an estimated 200,000-400,000 company directors who currently use HMRC's free tool. If that's you, now is the time to pick an alternative — not when your filing deadline is tomorrow.
What CT600 software needs to do
At minimum, any CT600 filing solution must:
- Calculate Corporation Tax correctly — including the current multi-rate system (19%/25% with marginal relief)
- Generate iXBRL accounts — HMRC has required accounts in iXBRL format since 2011
- Submit directly to HMRC — via the Government Gateway XML API
- Handle financial year splits — accounting periods spanning 1 April need split calculations
Beyond the basics, look for:
- Plain-English interface (not HMRC box numbers)
- Error checking before submission
- Automatic marginal relief calculation
- Capital allowances calculation
- Support for micro-entity and small company accounts
Your options in 2026
1. Taxpipe
Price: £59 one-time per CT600 return Best for: Sole directors, freelancers, contractors, micro-entities, small companies
Taxpipe is purpose-built for company directors who want to file their own CT600 without hiring an accountant. It uses a guided wizard that asks plain-English questions instead of showing you HMRC box numbers.
What it does well:
- Complete guided flow — about 15 minutes from start to submission
- Automatic tax computation with marginal relief
- iXBRL micro-entity accounts (FRS 105) and small company accounts (FRS 102 Section 1A) included
- Direct HMRC submission with real-time status tracking
- No accounting knowledge required — questions are in plain English
- One-time fee, no subscription
- 100% money-back guarantee
Limitations:
- No support for group companies or consolidated accounts
- No R&D tax credit claims (yet)
- No VAT or PAYE integration
- New to the market (launched 2026)
Verdict: The most affordable option for straightforward returns. The guided approach means you don't need to know which CT600 box is which. Good for the 80% of companies with simple finances.
2. TaxCalc
Price: From £77 + VAT per year (Self Assessment + Corporation Tax bundle) Best for: Directors who also need to file Self Assessment
TaxCalc has been around since 2001 and covers both personal and business tax. Their Corporation Tax module handles CT600 filing with iXBRL.
What it does well:
- Established product with long track record
- Covers Self Assessment and Corporation Tax
- Desktop and cloud versions available
- Good customer support
Limitations:
- Annual subscription even if you only file once
- Interface can feel dated
- Steeper learning curve than purpose-built CT600 tools
- Prices increase each year
3. GoSimpleTax
Price: From £58.50 per year (Corporation Tax plan) Best for: People who also use their Self Assessment product
GoSimpleTax started as a Self Assessment tool and added Corporation Tax. Their CT600 module handles the basics.
What it does well:
- Clean, modern interface
- Good for people already using GoSimpleTax for Self Assessment
- Bank feed integration
Limitations:
- Annual subscription
- Corporation Tax module is newer, less mature
- Limited iXBRL account types
- Support can be slow during peak filing season
4. Xero + filing add-on
Price: From £15/month for Xero + additional CT600 filing costs Best for: Companies that want full bookkeeping + filing in one place
Xero is accounting software first, not filing software. You'll need a CT600 filing add-on or to export data to separate filing software.
What it does well:
- Comprehensive bookkeeping and invoicing
- Bank feeds and reconciliation
- Large ecosystem of integrations
- Good for ongoing accounting, not just annual filing
Limitations:
- Monthly subscription adds up (£180+/year minimum)
- CT600 filing isn't built in — needs third-party add-on
- Overkill if you just need to file a CT600 once a year
- Complex setup for a simple company
5. FreeAgent
Price: From £14.50/month (£174/year minimum) Best for: Freelancers and contractors who want bookkeeping + filing
FreeAgent is popular with freelancers and includes Corporation Tax filing. It's a full accounting package.
What it does well:
- Built for freelancers and small companies
- CT600 filing included
- Time tracking and invoicing
- Clean interface
Limitations:
- Monthly subscription (expensive just for annual CT600 filing)
- Not the best for companies with complex needs
- iXBRL generation can be finicky
- You're paying monthly for something you use once a year
6. Hire an accountant
Price: £500 – £1,500+ per year Best for: Complex companies, R&D claims, group structures, tax planning
The traditional option. An accountant prepares your accounts, calculates your tax, and files the CT600.
What they do well:
- Professional advice and tax planning
- Handle complex situations (R&D, groups, overseas)
- Take responsibility for accuracy
- Can represent you if HMRC enquires
Limitations:
- Expensive for simple companies
- Turnaround time (weeks, not minutes)
- Back-and-forth for information
- You still need to provide all the raw data
- Quality varies hugely between firms
Comparison table
| Feature | Taxpipe | TaxCalc | GoSimpleTax | Xero | FreeAgent | Accountant |
|---|---|---|---|---|---|---|
| Price | £59 once | £77+/yr | £58.50+/yr | £180+/yr | £174+/yr | £500+/yr |
| CT600 filing | ✓ | ✓ | ✓ | Add-on | ✓ | ✓ |
| iXBRL accounts | ✓ | ✓ | ✓ | Via add-on | ✓ | ✓ |
| HMRC submission | ✓ | ✓ | ✓ | Via add-on | ✓ | ✓ |
| No subscription | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
| Plain English | ✓ | Partial | ✓ | ✗ | ✓ | N/A |
| Time to file | ~15 min | ~30 min | ~30 min | Varies | ~30 min | Weeks |
| Self Assessment | ✗ | ✓ | ✓ | ✗ | ✓ | ✓ |
| Bookkeeping | ✗ | ✗ | ✗ | ✓ | ✓ | Optional |
| Money-back guarantee | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
How to decide
Choose Taxpipe if: You have a simple company, want the lowest cost, and just need to file your CT600 once a year. No subscription, no complexity.
Choose TaxCalc/GoSimpleTax if: You need Self Assessment filing too, and don't mind an annual subscription.
Choose Xero/FreeAgent if: You want year-round bookkeeping, invoicing, and bank feeds alongside CT600 filing. Worth it if you'll use it monthly.
Choose an accountant if: Your company has complex structures, you're claiming R&D credits, or you want tax planning advice. The cost is justified by expertise.
The bottom line
For the ~200,000 company directors who've been using HMRC's free tool, the question isn't whether to switch — it's where. If your company has straightforward finances and you just need to file a CT600, paying hundreds for accounting software or an accountant doesn't make sense.
The market has shifted toward simple, affordable filing tools that do one thing well. That's the gap HMRC's closure creates, and it's exactly what newer tools like Taxpipe are built to fill.
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