This guide explains how to sign up for and use the HM Revenue & Customs (HMRC) Self Assessment for Agents Online Service.
You can use the service to set up authorisations for Self Assessment, send tax returns and view statements online.
On this page:
HMRC's Self Assessment for Agents online service allows you to carry out many tasks online on behalf of your clients. It is safe, secure and reliable. You must sign up for this service whether you plan to use HMRC Online Services or commercial software to send your clients' tax returns.
You can use the online service to:
See a demonstration of the Self Assessment for Agents online service
Using the online service offers a number of benefits over sending paper returns, including:
If you wish to send a paper tax return on behalf of your clients, generally it must reach HMRC by midnight on 31 October.
If you send it online, you get longer - the deadline for submitting your tax return is midnight on 31 January.
If you've not already registered as an agent for Self Assessment and wish to act on your clients' behalf for Self Assessment matters, you need to write to HMRC to do so. You'll then receive a Self Assessment agent code which you'll need before you can set up the online service.
How to obtain an agent code for Self Assessment
Once you have your Self Assessment agent code, there are two ways of signing up for the online service.
You should log in to HMRC Online Services and add the Self Assessment 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 Self Assessment 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 by post within seven days of registering for Self Assessment 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 Self Assessment for Agents you need to go through the client authorisation process for each client. When you've been through this process, HMRC can deal with you online, by phone or in writing about each of your clients' Self Assessment matters.
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 tax return 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
You can view your Self Assessment clients' PAYE Coding Notices online if certain conditions apply. But first, you must register for HMRC Online Services and enrol and activate the Self Assessment for Agents online service (see previous sections for more information).
You will then be able to view PAYE Coding Notices online if both the following conditions apply:
But please note: if your client previously had an agent who was registered for the Self Assessment for Agents online service, or if your client was registered for the service in their own right at the time the Coding Notice was issued, you may be able to view any notices issued on or after 11 October 2011, even if you became their authorised agent at a later date.
In due course, you'll be able to view PAYE Coding Notices - issued on or after 11 October 2011 - for the:
Generally, Coding Notices will be available to view online 72 hours after they are issued.
Once you're authorised to act on behalf of your client, you can view their statements, tax liabilities and payments online.
You can also view and download your full client list.
See a demonstration of Self Assessment for Agents online service
When you send your client's tax return online using Self Assessment for Agents you can use either:
You can use HMRC's online service to send the main Self Assessment tax return - form SA100 - and most supplementary pages. The online service checks the return as you fill it in and does the tax calculations for you.
You can also get free technical support from the Online Services Helpdesk.
Contact the Online Services Helpdesk
You can use commercial software to send your client's tax return online. Commercial software also allows you to file the partnership return (form SA800) and the trust return (form SA900) as well as other Self Assessment forms.
HMRC provides a list of commercial software suppliers whose software has been tested to make sure it's compatible with HMRC's systems.
Find out about Self Assessment Online and commercial software
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' Self Assessment 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)
Find practical advice to help you manage Self Assessment 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
