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).
Prepare your company accounts and Corporation Tax return (CT600) in one place. After you review and approve the filing, the platform sends it to the destinations you choose using your credentials. For CICs, it sends the CT600 to HMRC and prepares an accounts and CIC34 ZIP package for you to upload to Companies House.
WHAT'S INCLUDED
What you can file.
Statutory company accounts
Dormant or micro-entity FRS 105 accounts. CICs download a package to upload to Companies House.
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.
CT600 filing for community interest companies
Eligible micro-entity CICs can file their CT600, tax computation and accounts with HMRC through us. Complete the CIC34 questions to prepare a Companies House package containing your accounts and report. Download the ZIP and upload it yourself through the Companies House CIC accounts service.
CIC accounts and CIC34: step-by-step guide →WHY US
Why use SimpleCompanyTax.
No accounting knowledge required
Plain-English questions, no jargon, inline help on every field.
Faster than an accountant
Filings take under 30 minutes end-to-end.
Purpose-built
For eligible micro-entities using FRS 105 and supported dormant companies. Check the full eligibility rules and filing scope.
Everything in one place
Accounts, CT600 and HMRC filing in one place. Supported Companies House filings are included. CICs upload their package themselves and pay the separate Companies House fee.
3 STEPS
How it works.
- 01
Enter company details
Choose your company. We prefill available Companies House details.
- 02
Answer simple questions
A guided wizard walks you through income, expenses, and anything special about the period.
- 03
Review and submit
Check your documents, enter your credentials and select Submit. The platform sends the filing. For CICs, you upload the Companies House package.
Two simple prices per company, per year.
One flow for HMRC and Companies House. Pick the tier that matches your trading status, with no per-filing surcharges for supported filings.
Dormant filings
Dormant company
No trading activity during the period
£10 +VAT / company / year
- Dormant accounts to Companies House
- Nil CT600 to HMRC
- Unlimited revisions & downloads
- AES-256 secure storage
UK VAT illustration: £10.00 + £2.00 VAT (£12 total)
Most companies
Micro-entity
Eligible active micro-entity company filing under FRS 105
£25 +VAT / company / year
- FRS 105 accounts to Companies House
- CT600 + iXBRL with full tax computation
- Marginal relief + fiscal-year apportionment
- Unlimited revisions & downloads
UK VAT illustration: £25.00 + £5.00 VAT (£30 total)
FIT
Who it's for.
Micro-entities
Eligible micro-entity companies using FRS 105. For periods beginning on or after 6 April 2025, the size test uses at least two of three limits: annual turnover no more than £1,000,000, balance sheet total no more than £500,000 and an average of no more than 10 employees. Adjust turnover for the accounts-period length and apply the qualifying-year rules and exclusions. 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 you file to both HMRC and Companies House?
Yes, for supported company filings. You review the documents, enter your own filing credentials and select Submit. The platform sends the filing to the destinations you selected. Support staff do not send it manually. Check each authority’s response separately. CIC accounts use a separate package that you upload to Companies House yourself.
See the three options →Can I file for a community interest company (CIC)?
Yes. #Simple CompanyTax supports eligible micro-entity CICs limited by shares or by guarantee. We file your CT600, tax computation and accounts with HMRC. Choose Simplified or Detailed in the CIC34 report card on Financial Data and complete the questions to prepare your Companies House ZIP package, containing your accounts and CIC34 report. You download and upload it yourself through the Companies House CIC accounts service, which charges a separate £15 fee. Leave the report selector on None if you only want the CT600 filing route.
File your CIC accounts and CIC34 report →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?
Yes, for eligible micro-entities with prepared figures. Can I file company tax myself?
Start filing now.
File your company accounts and CT600 online with HMRC and Companies House in one flow, from £10 +VAT/year.