Your CT600 and company accounts, filed together.
Clients Assistant prepares your company's Corporation Tax return and accounts from one set of figures. It works out the tax, marginal relief included, then files the CT600 with HMRC and the accounts with Companies House.
Filing opens soon. We're completing HMRC's approval for filing Company Tax Returns. Prepare your returns free now, and register your interest to be emailed the day filing opens.
Start preparing for freeFrom company number to filed return
Find your company
Enter the company number. Its name, address and filing deadlines come from Companies House, and last year's figures can be read from the accounts already on the register.
Bring in the figures
Take them from your Clients Assistant ledger, upload a trial balance from Xero, QuickBooks or Sage, or use our Excel templates. Review the computation, the accounts and the CT600 before anything is sent.
File and follow it through
Send the CT600 to HMRC and the accounts to Companies House, then watch each one in the submission history until it's accepted.
Books in Clients Assistant, or somewhere else.
Already keep your books in Clients Assistant? The return picks up the year's figures straight from your ledger. Use Xero, QuickBooks or Sage? Upload the trial balance you export from it. Keep your books in a spreadsheet or another package? Fill in the Excel template made for your kind of company (trading, property letting, charity or community interest company) and upload it, or type the figures in.
- Trial balance import: Xero, QuickBooks and Sage exports read as they are, with each account sorted for you to check
- Excel templates for trading companies, letting companies, charities and CICs, each asking only what applies (the CIC's includes the CIC34 report)
- Checked against HMRC's rules before you send it, so problems show up while you can still fix them
- HMRC's and Companies House's replies collected for you, with every message kept on the return
- Amend a return you've already filed, from the same figures
- Invite colleagues or your accountant by email to prepare and file the company's returns with you
- Optional two-step sign-in: a code from an authenticator app as well as your password, so a stolen password alone can't open your account
The awkward parts, handled
Marginal relief
Worked out for profits between £50,000 and £250,000, with the limits shared between associated companies.
Long periods split
A period of account of up to 18 months becomes two CT600 returns, set up for you.
Accounts and CT600 together
Micro-entity, small or dormant accounts for Companies House, and the CT600 for HMRC, from the same figures.
Last year's figures
Comparatives read from the accounts on the Companies House register, or from last year's files.
Dormant companies
A dormancy check against the company's filing record and books, then dormant accounts in the right form.
Charities and CICs
CT600E pages for charities. For CICs, the accounts and CIC34 report as one package.
Directors' loans
CT600A for loans to participators, with the tax on loans still outstanding nine months after the year end.
Deadline reminders
Emails ahead of the accounts, CT600, tax payment and confirmation statement deadlines, kept up to date from Companies House.
Free to prepare. Pay when you file.
Get the whole return ready, and see what's owed, before you pay anything. You only subscribe when you're ready to file.
All prices exclude VAT. Customers are charged 20% VAT on top at checkout — so £5 a year is £6.00 including VAT.
Plans open with filing. While we complete HMRC's approval, preparing returns is free, and the plans below can be bought once filing opens. Register your interest to hear when.
- Company details and deadlines from Companies House
- Tax computation, accounts and CT600 previews
- Checks against HMRC's rules
- Deadline reminders by email
- Trading company£15 + VAT
- Dormant company£5 + VAT
- Everything in Prepare
- File the CT600 with HMRC
- File the accounts with Companies House
- CIC package, amendments and the full submission history
- Up to 3 companies£35 + VAT
- Up to 12 companies£125 + VAT
- Up to 50 companies£250 + VAT
- Up to 150 companies£460 + VAT
- Up to 250 companies£550 + VAT
- Up to 500 companies£625 + VAT
- Up to 1,000 companies£800 + VAT
Books kept elsewhere? Start here
Pick the template for your kind of company. Each asks only the questions that apply to it, checks itself as you fill it in, and uploads straight into a new return. In Clients Assistant, the right one is offered for the company you've chosen.
Trading company template
The year's figures for a company that trades, ready to upload. Covers a company that also lets property.
ClientsAssistant_CT600_Trading_Template.xlsxProperty letting template
For a company whose business is letting property: rents, mortgage interest and letting allowances.
ClientsAssistant_CT600_Property_Template.xlsxCharity template
For a charitable company: the statement of financial activities by fund, the trustees' report and the CT600E.
ClientsAssistant_CT600_Charity_Template.xlsxCommunity interest company template
For a CIC: the year's figures and the CIC34 community interest report.
ClientsAssistant_CT600_CIC_Template.xlsxTrial balance template
For software other than Xero, QuickBooks or Sage: paste in your trial balance, choose a type for each account, and upload it.
ClientsAssistantTrialBalanceTemplate.xlsxCorporation Tax, in plain terms
A UK limited company pays Corporation Tax on its profits. Each year it files accounts with Companies House and, when HMRC sends it a notice to file, a Company Tax Return (the CT600). The CT600 has to be filed online, with a copy of the accounts and the tax computation.
Profits up to £50,000 are taxed at 19% and profits over £250,000 at 25%. In between, the company pays 25% less marginal relief, so the rate rises gradually instead of jumping.
Every year, a company needs to:
- Prepare its statutory accounts
- File them with Companies House
- Work out its taxable profits and the tax due
- Pay the tax by the deadline
- File the CT600, with the accounts and computation, with HMRC
What's due after your year end
For a private company that isn't large, counting from the end of its accounting period.
The accounting period closes. Start preparing the accounts and return.
Accounts due at Companies House (21 months after incorporation for a new company's first accounts).
Corporation Tax payment due to HMRC.
CT600 due at HMRC, with the accounts and tax computation.
Questions people ask
Yes. You can set up the company, build the return, see the tax computation, preview the accounts and the CT600, and check it against HMRC's rules without paying. You only subscribe, from £5 + VAT a year per company, when you're ready to file with HMRC or Companies House.
No. If you keep your books in Clients Assistant the figures come straight from your ledger. If you keep them elsewhere, upload a trial balance from Xero, QuickBooks or Sage, fill in the Excel template for your kind of company (trading, property letting, charity or community interest company), or type the figures in.
Yes. Export the trial balance at the company's year end and upload it as it is, in Excel or CSV. Clients Assistant reads each account and sorts it into turnover, expenses, assets, liabilities or capital from the account types and codes in the file. You check every line before the return is created, and choose a type for any it can't place, such as a suspense account. Your choices are remembered for next year. Using other software? Copy your trial balance into our trial balance template.
For profits between the lower and upper limits, relief is 3/200 of the difference between the upper limit and your profits, scaled when the company has exempt distributions. Both limits are divided between associated companies and reduced for a period shorter than twelve months, and a period that spans 1 April is split between the two financial years.
A CT600 can only cover up to 12 months, so a period of account of up to 18 months is split into two returns: the first 12 months, then the rest. Clients Assistant creates both for you from the one set of accounts.
Yes. Clients Assistant checks the company's record at Companies House and its books to see whether it is dormant, and prepares dormant accounts in the right form. Filing for a dormant company is £5 + VAT a year.
Charities can file the CT600 with the CT600E supplementary pages, claiming exemption on income applied for charitable purposes. Community interest companies get their accounts and CIC34 report prepared as one package, ready to file on Companies House's CIC service. Each has its own Excel template: the charity's covers its funds, trustees' report and CT600E, and the CIC's includes the CIC34 report.
HMRC and Companies House first acknowledge the submission. Clients Assistant then collects their final answer for you and shows it on the return. Every message is kept in the submission history, and you can open any entry to see exactly what HMRC or Companies House said.
Yes. An admin invites each person by email from the Users page. They accept by creating an account, or by signing in with an existing Clients Assistant account. They can then prepare and file the company's Corporation Tax return and accounts with you. Each plan includes a set number of users per company; a company without a subscription has only the person who set it up.
Your account is protected by your password, and you can add two-step sign-in for free. Turn it on under Settings > Business Setup > Sign-in Security: after your password, you enter a 6-digit code from an authenticator app on your phone, such as Google Authenticator or Microsoft Authenticator, so someone who learns your password still can't sign in. It's optional, and you can turn it off at any time. If you lose your phone, an admin of your company or Clients Assistant support can reset it, and we email you whenever that happens.
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