Corporation Tax Return (CT600)
Submitted electronically to HMRC in the required XML format, with an IRmark receipt.
SOLUTION · Updated 22 April 2026
File company accounts & CT600 online (UK).
Submit your company accounts and corporation tax return (CT600) in one place. Our software guides you step by step and submits directly to HMRC and Companies House — no accountant, no spreadsheets, no Government Gateway gymnastics.
WHAT'S INCLUDED
What you can file.
Statutory company accounts
Submitted to Companies House — dormant, micro-entity FRS 105, or small company FRS 102 (1A).
iXBRL accounts
Generated automatically with the correct tags so HMRC can machine-read your numbers.
Supporting tax computation
The bridge between accounting profit and taxable profit, produced for you.
WHY US
Why use SimpleCompanyTax.
No accounting knowledge required
Plain-English questions, no jargon, inline help on every field.
Faster than an accountant
Most micro-entity filings take under 30 minutes end-to-end.
Purpose-built
For micro-entities and dormant companies. We don't try to be everything — we nail the 90% case.
Everything in one place
Accounts, CT600, iXBRL, HMRC submission, Companies House submission — one flow, one login, one price.
3 STEPS
How it works.
- 01
Enter company details
Connect to Companies House — we prefill what we can.
- 02
Answer simple questions
A guided wizard walks you through income, expenses, and anything special about the period.
- 03
Review and submit
Check the computation, preview the accounts, then file directly to HMRC and Companies House.
Two simple prices per company, per year.
One flow for HMRC + Companies House. Pick the tier that matches your trading status — no per-filing surcharges either way.
Dormant filings
Dormant company
No trading activity during the period
£10 / company / year
- Dormant accounts to Companies House
- Nil CT600 to HMRC
- Unlimited revisions & downloads
- AES-256 secure storage
Most companies
Micro-entity
Trading company filing under FRS 105
£25 / company / year
- FRS 105 accounts to Companies House
- CT600 + iXBRL with full tax computation
- Marginal relief + fiscal-year apportionment
- Unlimited revisions & downloads
FIT
Who it's for.
Micro-entities
FRS 105 accounts + CT600 in one go. Learn more →
Dormant companies
Dormant accounts to Companies House and, if needed, a nil CT600 to HMRC. File dormant →
Small trading companies
Straightforward single-entity UK companies without groups, overseas activity, or R&D claims.
FAQ
Frequently asked.
Do I need to file both accounts and a CT600?
In almost all cases, yes. Companies House wants your statutory accounts; HMRC wants the CT600 with iXBRL-tagged accounts attached. Two separate submissions with separate deadlines — but we handle both in one flow.
Can I submit both together?
You can initiate both from the same review screen. We send the accounts to Companies House and the CT600 (with iXBRL accounts) to HMRC, and surface the receipts for both. Companies House is 9 months after period end; HMRC's CT600 is 12 months.
What if my company is dormant?
We prepare dormant accounts for Companies House using the correct template, and if HMRC still requires a CT600 we file a nil return. See dormant accounts and dormant CT600.
What is a CT600 exactly?
It's the electronic form HMRC uses for corporation tax. What is a CT600?
Can I really do this without an accountant?
For micro-entities with simple finances — yes, easily. Can I file company tax myself?
Start filing now.
File your company accounts and CT600 online — HMRC and Companies House, one flow, from £10/year.