The HM Revenue & Customs (HMRC) Corporation Tax for Agents Online Service enables you to submit your clients' Company Tax Returns over the internet and manage other aspects of their Corporation Tax affairs. It is safe, secure and reliable.
Corporation Tax and related payments must be paid electronically. You must also submit your clients' Company Tax Returns (including supporting documentation) online.
This guide will help you set up and use the HMRC Corporation Tax for Agents Online Service. You need to sign up for this online service whether you're planning to use HMRC's free software or commercially available software to file your clients' returns.
On this page:
HMRC's Corporation Tax for Agents online service allows you to carry out many tasks online on behalf of your clients. It is safe, secure and reliable.
You can use the online service to:
View a demonstration of Corporation Tax for Agents
If you've not already registered as an agent for Corporation Tax, you need to do so. You'll receive a Corporation Tax agent code which you need to sign up for the online service.
How to get an agent code for Corporation Tax
Once you have your Corporation Tax agent code, there are two ways of signing up for the online service.
You should log in to HMRC Online Services and add the Corporation Tax for Agents service to your portfolio from the 'Services you can add' section of 'Your HMRC services'.
Log in to HMRC Online Services
You need to register for HMRC Online Services then enrol for the Corporation Tax for Agents online service by following the steps below:
The registration process only takes a few minutes to complete. You'll have to:
HMRC will send you an Activation Code (also known as an Activation PIN) by post within seven days of registering for Corporation Tax for Agents. You must activate the service within 28 days of the date on the letter otherwise you'll have to start this process again.
Register as a new agent user through HMRC Online Services
If you have your User ID and password but you have not received your Activation Code within 28 days of registration, you should check with the Online Services Helpdesk to ensure that HMRC has your correct address and postcode.
Contact the Online Services Helpdesk
If the Activation Code has been lost or has expired, you can request a new code online through the Government Gateway website.
Read more about lost or expired Activation Codes
Go
to the Government Gateway website (Opens new window)
Once you've signed up for Corporation Tax for Agents, you need to go through the authorisation process for any new or previously unauthorised client.
To submit an online authorisation request for your client you'll need:
Please note: the authorisation code can take up to seven days to arrive. You will need to enter the code before the client will appear on your client list, so ideally you need to do this well in advance of their return filing deadline. You must enter the code within 30 days from the date on the letter, otherwise it will expire.
Get client authorisation using HMRC Online Services
View a demonstration of client authorisation and management
Virtually all companies and organisations must submit their Company Tax Returns online. As well as this, companies must file accounts and computations in a set format - Inline eXtensible Business Reporting Language (iXBRL).
If you represent unincorporated organisations and some charities that don't need to prepare statutory accounts under the Companies Act, you can submit their accounts in PDF format. But you must submit any tax computations in iXBRL format.
Corporation Tax and related payments must be made electronically.
Commercial software may be better suited to your clients' circumstances and your own business needs, as generally, these products offer greater flexibility and choice of supplementary pages. HMRC works closely with software developers to test their products to ensure they are compatible with HMRC systems. It's a good idea to consider whether your software will be able to handle iXBRL formatting - particularly if you're thinking of investing in new software.
If you use an integrated software package or stand-alone accounts software, your software will automatically insert the majority of the necessary iXBRL tags and produce an iXBRL accounts file. If you enter data into freeform boxes that don't have a pre-defined description and iXBRL tag, most software includes functionality to help you identify and add the correct iXBRL tag yourself.
The Corporation Tax online service also supports a 'test in live' facility for commercial software users. If your software allows this, you can use this facility to submit a sample Company Tax Return to HMRC as a test before submitting the actual return. Your supplier will tell you if your software supports the 'test in live' facility.
Follow the link below to view a list of commercial software that has been tested for compatibility with HMRC's online systems.
Please note: HMRC does not expect you to have to change software suppliers in order to submit your clients' Company Tax Returns on time. If the delivery date of particular iXBRL-enabled software prevents you from submitting your returns on time, HMRC will consider this sympathetically. Follow the link below to find more information about managing the transition to filing online and using iXBRL.
Corporation Tax Online - successfully tested commercial software
If you choose to use HMRC's free software, you can submit the following forms for your clients online:
You can also submit accounts and computations for your clients using templates that automatically send your clients' data in the right format. The accounts template also includes a joint filing option. You can choose to enter a client's company accounts information once and then submit that information to HMRC (as part of your client's Company Tax Return) and to Companies House using a 'one stop' online facility.
Read more about the company accounts joint filing service
But you don't need to use the HMRC templates. You can attach your clients' accounts and computations to the HMRC online CT600 form in either iXBRL or PDF format. But remember that for most companies, you'll need to attach their accounts and computations in iXBRL format (for more information, follow the links below).
Please note: the accounts template within HMRC's free software is not suitable for accounts prepared by charities. Until HMRC provides a template that is suitable, smaller charities can choose to send their accounts to HMRC in iXBRL format (using commercial software) or as a PDF. Follow the link below to find out more about what HMRC means by 'smaller charities' and what format is acceptable for their accounts.
If you're using HMRC's software, you can also attach other relevant items that are required as part of your return, for example claims or elections, reports or statements. These attachments must be in PDF format. The maximum size for combined attachments when using HMRC's free software is 5MB.
You can only include one iXBRL statutory accounts file as part of your client's online Company Tax Return. If iXBRL accounts are being included as part of the online return, any additional accounts forming part of the return must be attached as PDF files.
HMRC also performs a number of validation checks at the point when a return is submitted online. These checks ensure that:
A return will be rejected if it fails any of these checks.
A validation check is also carried out on some iXBRL tags when the return is submitted online. These include the 'start' and 'end' date tags for the company accounts and the name of the director approving the balance sheet. But these checks can't confirm that an iXBRL tag has been applied correctly. In line with current HMRC practice, Corporation Tax Online is a 'process now, check later' service. The iXBRL tags will be used in HMRC's risk analysis and will help inform the selection of the returns for further compliance review. Some returns will also be reviewed to ensure the completeness and accuracy of the iXBRL tags used.
Detailed guidance on Corporation Tax online filing and electronic payment
Find out more about Corporation Tax Online
See a demonstration of the Corporation Tax for Agents online service
Company Tax Returns for smaller charities: filing online - format for accounts
Once you're authorised to act on behalf of your client online, you can view their Corporation Tax position for different accounting periods and their latest liabilities and payments online.
If your client has a Group Payment Arrangement in place, you can view a summary of the group's liabilities and payments made for the last five years by looking at the nominated company's online account.
View a demonstration of Corporation Tax for Agents online service
You can update contact details and addresses for communication for any clients who are incorporated businesses. If your client is unincorporated, such as a club or association, you can change details of their name, address and contact details.
You'll also be able to change your own address and contact details.
Please note: you can't make changes to a limited company's registered name or office. Instead you must tell Companies House about the change and they will then advise HMRC automatically.
See a demonstration of Corporation Tax for Agents
The first person to set up your HMRC online agent account is called an 'administrator' for online service purposes. The administrator can appoint other administrators and/or assistants to help you manage your clients' Corporation Tax matters online. This is a useful facility if you want to allocate specific clients to different people in your organisation. You set up administrators and assistants on the Government Gateway website.
Read more about how to manage users and assistants
Log in to your Government Gateway account (Opens new window)
All Corporation Tax and related payments must be made electronically. Related payments include interest charged on overdue Corporation Tax and penalties for not filing your Company Tax Return on time.
You can pay electronically online using:
You can also pay electronically but not online using:
Read more about paying Corporation Tax
Some tax agents and advisers may need detailed guidance on Corporation Tax online filing, the requirement to use iXBRL format for accounts and computations, and electronic payment requirements. For example, you may need to know what to do if:
Follow the link below for further information on all these topics.
Detailed guidance on Corporation Tax online filing and electronic payment
HMRC has provided answers to some commonly asked questions about Corporation Tax online filing and electronic payment.
Find answers to commonly asked questions
Find practical advice to help you manage Corporation Tax for your clients
How to register your client's business with HMRC
What counts as reasonable excuse when an online tax return is filed late
