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Sending your tax return online

If you send your return online, you can tailor it and just complete the pages you need. You get online help as you work through the form. Your tax is worked out automatically and you get an acknowledgement when HM Revenue & Customs (HMRC) receives your return. You have longer to send in the return than if you use a paper form. You have until 31 January following the end of the tax year instead of 31 October.

You need to register for HMRC Online Services if you want to send your return online.

• Self Assessment Online - the benefits and how to register

Filling in a paper tax return

Completing the main Tax Return (SA100)

You usually receive a letter in April each year telling you to complete your tax return. If you want to send your return on paper, you can download the forms or order them from HMRC.

Make sure that you put your ten-digit tax reference number, called your Unique Taxpayer Reference, on your tax return if you download it. You'll find this reference number on statements and letters from HMRC.

You use the main tax return form (SA100) to give basic details such as your name, address and straightforward investment income.

You may need some supplementary pages to tell HMRC about other income and gains, for example income from employment, income from property, or capital gains. Each supplementary page has a helpsheet to help you fill it in.

If you complete your tax return online instead, you don't need all these different forms. You just add the pages you need as you go.

• Self Assessment forms, helpsheets and supplementary pages Opens new window

• Order Self Assessent forms Opens new window

• File your tax return online

Completing the short tax return (SA200)

You can only fill in the Short Tax Return if HMRC decides to send you the form to complete. You can't do any of the following:

• order it
• download it
• ask HMRC to send you this form
• use a form that has been sent to someone else

HMRC will only send you this form if your tax affairs are straightforward. They will also send you a guide to help you complete it. Please check the list in the guide to make sure that it's the right form for you before you fill it in.

You may prefer, however, to send your tax return online instead. It's straightforward and you can tailor your return online so that you only add the pages you need. You must register for HMRC Online Services first.

• File your tax return online

Tax return records you may need

For the tax year (6 April to the following 5 April) you'll need records relating to:

• any employment
• pension contributions you make or any pension you receive
• income you might get from letting a property or land
• any capital gains or losses you have made during the tax year

You may also need records relating to:

• UK savings and investments
• UK pensions, annuities and benefits
• life insurance gains and AVC refunds
• any other taxable income
• gifts to charity, if you're claiming tax relief
  

You'll need to provide your bank details if you want any tax repaid directly to your account. HMRC recommends this as it is quick and secure.

• Record keeping (individuals and directors)

If you don't have exact figures for your tax return

If you don't have exact figures you can use:

• an estimate - a figure you want HMRC to accept as your final figure
• a provisional figure - one you want to use until you can confirm the actual amount

If you use a provisional figure, you must tell HMRC when the actual figures will be available.

You should use the 'Additional Information' section to say how you arrived at the figures and why you can't use actual figures. If adjustments are made at a later date and you haven't paid enough tax, you may have to pay interest and penalties.

Deadlines for sending your tax return

If you send in a paper tax return, it must reach HMRC by midnight on 31 October. If you miss this deadline, you'll need to send your return online instead. If you don't, you'll have to pay a penalty.

You should send your return back in the envelope provided or send it to the Tax Office shown on the front page of the form. You won't get a receipt if you send a paper tax return.

If you have downloaded the form it may not show a Tax Office address. You'll need to check your Self Assessment statement - or a letter from HMRC - to find the right address to send it to. Alternatively, you can follow the link below to find an address. Make sure that the form also shows your ten-digit taxpayer reference before you send it.

• Telephone or write to HMRC Opens new window

If you send your return online, it must reach HMRC by midnight on 31 January. You'll get an acknowledgment that HMRC has received your return. If you send your tax return back late, you'll have to pay a penalty, so make sure you send it on time.

• Tax return deadlines and penalties

Avoiding common mistakes on your tax return

If you make a mistake, HMRC may need to contact you before they can accept your return. So if you're sending a paper tax return:

• make sure you sign and date it
• check that you have completed and included any supplementary pages needed
• add your tax reference number, if you downloaded the form
• use the right form for the right tax year - don't just alter the date on an old form
• avoid putting notes on the return like 'information to follow'

You can avoid many mistakes by sending your tax return online, but make sure you:

• know what your User ID and password is, don't leave it until the last minute to check
• read any error messages, for example you may have used text or punctuation that aren't accepted
• re-enter your User ID and password to submit your return
  

You'll need to register to use HMRC Online Services to send your tax return, even if you use commercial software.

• Self Assessment online - the benefits and how to register

If you have problems completing your tax return

If you need help with filling in your tax return, you can ring the HM Revenue & Customs Self Assessment Helpline.

• Contact the Self Assessment Helpline Opens new window

What happens after you've sent your return

You'll receive a tax calculation if you completed a paper tax return and asked for one. For online tax returns, you see this earlier, before you send your return.

If you are due a repayment of tax, you'll usually get this automatically. But it may be set off against other tax instead if there is an amount due soon.

If you have tax to pay, it will either be collected through your tax code or you will have to pay it by 31 January. Check your Self Assessment statement to find out more.

• Understanding your Self Assessment Statement