Understanding and using Self Assessment Online

If you're sending HM Revenue & Customs (HMRC) a Self Assessment tax return, you can do it online using the secure service HMRC provides. There are many advantages to filing or sending your tax return online instead of by paper, including automatic calculations, faster processing and later deadlines.

On this page:

Advantages of sending your tax return online
Deciding which way to send your return online
Using HMRC Online Services for the first time
If you've used Self Assessment Online before
If you have lost your User ID or password
Self Assessment Online service issues
Online Services Helpdesk
More useful links

Advantages of sending your tax return online

There are lots of advantages to sending your tax return online:

it's convenient, safe and secure - your account is encrypted, and protected by your chosen password and a unique User ID
you get an instant acknowledgment as soon as HMRC receives your tax return
your tax is worked out automatically, so you know what you owe or are owed right away
HMRC can repay any money you are owed more quickly than if you send a paper return
the deadline for online returns is later than for paper returns
you can complete your tax return at your own pace, saving it as you go
you can tailor your return, completing the right pages for your circumstances
you can store your completed return online and print out a copy for your records
you can view your Self Assessment payments and any amounts owed online
if you're self-employed, you can view liabilities and payments for your business taxes too
you can amend your contact details or use the secure email channel to ask HMRC a question
you can pay by Direct Debit - it's safe and secure, and you're less likely to miss a payment deadline

Tax return deadlines and penalties - find out more

Direct Debit payment - find out more

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Deciding which way to send your return online

You can use the free HMRC Self Assessment service or commercial software to send most tax returns online.

Some types of tax return aren't covered by the free HMRC Self Assessment service, but you can buy commercial software to send them online. These include:

SA900 - Trust and Estate Tax Return
SA800 - Partnership Tax Return
your personal tax return if it includes certain additional pages, for example if you're non-resident

You need to be registered to use HMRC Online Services before you can send your tax return online for the first time. This applies whether you use the free HMRC service or commercial software. See the section below for more information about using HMRC Online Services for the first time.

Tax returns you can't send online

There is currently no free HMRC Self Assessment service or commercial software for sending the following returns, so you will need to send them on paper:

SA700 – Tax Return for a non-resident company liable to Income Tax
SA970 – Tax Return for Trustees of Registered Pension Schemes

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Using HMRC Online Services for the first time

If you’re newly self-employed, HMRC will set up your Self Assessment Online account automatically when you register for business taxes.

If you're setting up a partnership, a Self Assessment Online account will automatically be set up for the Partnership.

In all other cases, you'll need to sign up to use HMRC Online Services yourself.

Information you need before you start

You'll need the following information:

your Unique Taxpayer Reference (UTR) number
either your postcode or National Insurance number (unless you live abroad)

You'll find your UTR on correspondence from HMRC. If you can't find it, you can contact the Self Assessment Helpline and ask for it to be sent to your home address. HMRC can't tell you your UTR over the phone.

If you haven't completed a tax return before (or it's been a while since you did), you may not have a UTR. You'll need to tell HMRC why you need a tax return, by registering for Self Assessment, so you can get a UTR.

Find out more about registering for Self Assessment

Contact the Self Assessment Helpline

Signing up for Online Services

If you already have a Self Assessment tax record and a Unique Taxpayer Reference, getting online with HMRC is a three-stage process, you:

sign up to use HMRC Online Services and select the relevant service(s) eg Self Assessment
wait for your Activation Code to arrive - it'll be sent to your home address and usually takes around seven working days
activate your account, you must do this within 28 days

If you registered online for business taxes after April 2012, your Self Assessment Online account will have been set up for you automatically. You'll just need to wait for your Activation Code to arrive and then activate your account.

Why do you need to wait for an Activation Code?

This is an added security measure to make sure that only you can use your account.

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If you've used Self Assessment Online before

If you've already registered for HMRC Online Services and activated your Self Assessment Online account, use the link below to log in and use Self Assessment Online.

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If you have lost your User ID or password

If you can't find your ID or your password, you can get a replacement. Go to the online services login page (see the link below), then follow the 'Lost User ID' or 'Lost password' links.

For security purposes you'll need to answer a number of questions before a replacement User ID or password is issued. Your ID or password will be sent to you online, if you've provided a current email address, or by second class post.

If you’ve lost both your User ID and password, you may be able to use the online form to request your User ID (see link below).

Use online form

Contact the Online Services Helpdesk

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Self Assessment Online service issues

For information on service availability and any technical issues with Self Assessment Online follow the links below. You’ll find the latest Self Assessment service availability details and information about any current service issues and how HMRC is dealing with them.

Check the availability of the Self Assessment Online service

Find out about any Self Assessment Online issues

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