HMRC closed its free CT600 filing service on 31 March 2026. SmallTax is here to fill the gap — at a fraction of the cost of an accountant.
File your CT600 &
company accounts in minutes
HMRC-recognised software for UK micro-entities. Submit your Corporation Tax return and iXBRL accounts directly to HMRC — no accountant needed.
Three steps to filed and done
Add your company details and enter income, expenses, and balance sheet. SmallTax guides you field by field — or connect Xero/QuickBooks to pull figures automatically.
SmallTax calculates your Corporation Tax liability, applies marginal relief, and generates your iXBRL accounts. Review everything before submitting.
One click sends your CT600 and accounts directly to HMRC over the Government Gateway. Confirmation comes back in minutes.
Everything you need, nothing you don't
CT600 & CT600A
Full Corporation Tax return including the CT600A supplement for close companies with loans to participators (s.455 CTA 2010).
iXBRL FRS 105 accounts
Inline XBRL-tagged micro-entity accounts covering the full P&L and balance sheet — ready for HMRC and Companies House.
Xero & QuickBooks connect
Connect directly to Xero or QuickBooks Online and pull your trial balance with one click. Accounts mapped to CT600 fields automatically.
AI trial balance import
Upload your trial balance from any software as CSV or Excel. AI automatically maps accounts to CT600 fields — review and apply in one click.
Direct HMRC submission
Files straight to HMRC via the Government Gateway API. No posting, no third-party agents, no delays. Confirmation back in minutes.
Practice dashboard
Multi-client view for accountants and bookkeepers: unified client list with urgency sorting, deadline tracking, and bulk filing tools.
CT600E for charities
Built-in charity supplement for registered charities, CASCs, and other exempt bodies — gift aid income, exempt income, non-qualifying expenditure.
Long period handling
Accounting periods over 12 months are automatically split into two CT600 returns per HMRC rules — SmallTax creates both and tracks their deadlines separately.
Built for the typical UK limited company
If your situation is more complex — groups, large company quarterly CT, audit requirements — SmallTax isn't the right tool. Speak to an accountant or consider a full practice management system.
Your financial data stays in the EU
End-to-end encryption, row-level database security, and enterprise-grade EU-hosted infrastructure. Your data never leaves UK/EU servers — SOC 2 Type II certified infrastructure, ISO 27001:2022 certified, UK GDPR compliant.
Pay once a year. File as often as you need.
All prices exclude VAT. No per-submission fees. No surprises.
For companies with no trading activity
- 1 dormant company
- CT600 nil return
- iXBRL micro-entity accounts
- Email support
For active trading companies
- 1 trading company
- CT600 & CT600A
- iXBRL FRS 105 accounts
- Full P&L and balance sheet
- Marginal relief calculation
- Priority email support
For accountants and bookkeepers
- Up to 10 companies
- All Solo features
- Multi-client dashboard
- Bulk filing tools
- Priority phone & email support
Need more than 10 companies? Get in touch.
Ready to file your CT600?
Join UK company directors filing with SmallTax. Create your account in seconds — no credit card required.
SmallTax is software, not tax advice. Consult a qualified accountant for complex matters.