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You should register with HM Revenue & Customs (HMRC) if you need to complete a Self Assessment tax return. For example you may have started self-employment or letting property. HMRC will then decide if you need a tax return. If you do, they'll set up your tax records and send you a Unique Taxpayer Reference.
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If your circumstances change you may need to fill in a Self Assessment tax return. On the return you tell HMRC about income or capital gains, or claim expenses or reliefs.
For example, you may have:
You need to register for Self Assessment before you complete your first tax return.
When you register you'll give HMRC the information they need to set up the right records for you. This helps to make sure you pay the right amount of tax and National Insurance at the right time.
For other changes in circumstances, simply complete the relevant boxes or supplementary pages on your Self Assessment tax return.
It's best if you register with HMRC as soon as your circumstances change. The latest you should register is by 5 October after the end of the tax year for which you need a tax return. The tax year runs from 6 April one year to 5 April the next.
If, for example, you have tax to pay on rent from a property in the 2012-13 tax year, you need to let HMRC know by 5 October 2013.
If you register late you may have to pay a penalty.
You will need:
How you register depends on your circumstances.
You can let HMRC know about your new self-employment by registering online for business taxes. You'll be asked for information about yourself and your business. HMRC will set up tax records for you using the information you provide, for example:
A Self Assessment Online account will be set up for you automatically at the same time.
If you've worked for yourself before, HMRC will already have Self Assessment records for you and you should have a Unique Taxpayer Reference already. You can find this on letters and Self Assessment statements from HMRC. You can still re-register online for Self Assessment, using the link below. It's the easiest way to make sure that HMRC have all the information they need. You'll need to register separately for other business taxes, such as PAYE for employers.
If you're starting or joining a new business partnership, both the partnership and each partner need to be registered for business taxes.
The partner nominated to receive and send in the Partnership Tax Return can register online. A Self Assessment Online account will automatically be set up for the partnership at the same time. If the partnership is employing other people, HMRC will use the information to set up PAYE records as an employer too.
If you're not the nominated partner, you still need to register as a partner in the business. HMRC will use the information you send to set up the right Self Assessment and National Insurance records for you.
You can do this online. It will help if you have information about the partnership to hand before you start, for example:
If a company, trust or another partnership becomes a partner in the partnership, it needs to be registered too. The person responsible for the new partnership, for example, the trustee or company secretary, should complete and sign form SA402.
You may need to complete a tax return because your circumstances have changed. You may, for example, have income from property or capital gains that you need to tell HMRC about. In this case you'll need to fill in the online form SA1 Registering for Self Assessment and getting a tax return.
Once you've registered for Self Assessment, HMRC will set up your records and send you a letter with a ten-digit reference, called a Unique Taxpayer Reference or UTR. You should keep your Unique Taxpayer Reference in a safe place.
If you're self-employed and you registered for business taxes online, accounts will automatically be set up for each HMRC Online Service that you selected. You'll receive an Activation Code for each service and you'll need to activate each one within 28 days.
In all other cases you'll need to sign up for HMRC Online Services yourself, before you can send your Self Assessment tax return online.
You'll get a letter, usually in April or May, telling you when you need to send your first tax return. HMRC may get in touch earlier if you need to send a tax return back for a previous tax year. If you don't receive a letter or a tax return, you should contact HMRC.
If you're self-employed as a sole trader or a business partner, you'll usually need to arrange to pay your Class 2 National Insurance contributions straight away too.
You may also need to register for VAT and the Construction Industry Scheme.