Best CT600 Filing Software UK 2026: Complete Comparison Guide
HMRC's free CT600 filing service closes 31 March 2026. Here's every option for filing your Corporation Tax return after that date.
Why You Need Software
From April 2026, all CT600 Corporation Tax returns must be filed using HMRC-recognised commercial software. The return must include:
- CT600 form data (electronically)
- iXBRL-tagged accounts
- iXBRL-tagged tax computation
You can't file on paper, and you can't use HMRC's free service.
The Options
1. Taxpipe — Best for Simplicity
taxpipe.co.uk | £59 per filing
| Pros | Cons |
|---|---|
| ✅ £59 one-off (no subscription) | ❌ New entrant (launched 2026) |
| ✅ Step-by-step wizard | ❌ No full accounting suite |
| ✅ Auto-generates iXBRL | |
| ✅ Marginal relief auto-calculated | |
| ✅ HMRC LTS + TPVS validated | |
| ✅ Free resubmission if rejected |
Best for: Single-company directors, dormant companies, micro-entities.
2. TaxCalc
taxcalc.com | ~£100-200/year
| Pros | Cons |
|---|---|
| ✅ Established (20+ years) | ❌ Annual subscription |
| ✅ Full CT600 + accounts | ❌ Steeper learning curve |
| ✅ Multi-company support | ❌ Desktop software |
| ✅ Agent support |
Best for: Accountants managing multiple clients.
3. TaxFiler
taxfiler.co.uk | ~£80-150/year
| Pros | Cons |
|---|---|
| ✅ Cloud-based | ❌ Annual subscription |
| ✅ CT600 + accounts + personal tax | ❌ Complex interface |
| ✅ iXBRL tagging | |
| ✅ Companies House filing too |
Best for: Accountants needing CT600 + personal tax in one package.
4. Xero / FreeAgent / QuickBooks / Sage
£12-40/month
These are accounting software that can prepare your accounts, but most don't file CT600 directly. You'd still need a separate tool for CT600 filing.
| Software | Files CT600? | Notes |
|---|---|---|
| Xero | ❌ (needs TaxFiler integration) | Great for bookkeeping |
| FreeAgent | ✅ (built-in) | Only for sole traders + small companies |
| QuickBooks | ❌ | Needs separate CT600 tool |
| Sage | ❌ (Sage Tax) | Separate product for filing |
5. An Accountant
£300-1,000+ per year
An accountant prepares your accounts AND files your CT600. This is the premium option — you pay for expertise, not just software.
| Pros | Cons |
|---|---|
| ✅ Expert advice | ❌ Expensive |
| ✅ Tax planning | ❌ You're dependent on their timeline |
| ✅ Error protection | |
| ✅ Audit support |
Best for: Companies with complex affairs, significant turnover, or specific tax planning needs.
Decision Matrix
| Situation | Best Option | Cost |
|---|---|---|
| Simple company, one return/year | Taxpipe | £59 |
| Dormant company | Taxpipe | £59 |
| Multiple companies | TaxCalc or TaxFiler | £100-200/year |
| Complex affairs | Accountant | £300+ |
| Already using FreeAgent | FreeAgent CT600 | Included |
| Want everything in one place | TaxFiler | £80-150/year |
What Happens If You Don't File?
If you don't file by your deadline (12 months after period end):
- Day 1 late: £100 penalty
- 3 months late: Another £100
- 6 months late: 10% of unpaid tax
- 12 months late: Another 10% of unpaid tax
Don't wait. Choose your software now and file on time.
Start with Taxpipe — £59, no subscription, file in 15 minutes.