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During the tax year (which runs from 6 April to 5 April) there are key dates for sending in your tax return and making payments. It's important that you're aware of these dates - HM Revenue & Customs (HMRC) can impose penalties and additional charges if you miss them.
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Soon after each new tax year (6 April) HMRC will contact you if they think you need to complete a tax return. This may be because you've completed a tax return before or because you've asked to complete a tax return.
If you send your return on paper, you'll receive a paper tax return. If you send your return online, you'll receive a letter instead (called the 'Notice to File').
If HMRC hasn't contacted you, but you think you need to complete a tax return, please follow the link below.
Find out if you need to complete a tax return
If you send in a paper tax return, it must reach HMRC by midnight on 31 October.
The deadline for paper tax returns is only later than 31 October if:
If you send your tax return online, it must reach HMRC by midnight on 31 January.
The deadline is earlier if you owe tax of less than £2,000 and you want HMRC to collect it by reducing your Pay As You Earn (PAYE) tax code next year. In this case you need to send your tax return online by 30 December instead. HMRC will try to amend your code number, but it's not always possible, and you may still have to make a payment instead by 31 January.
The deadline is only later than 31 January if you received the notice to file your tax return after 31 October. You'll then have three months from the date you receive the notice to send your return online.
HMRC doesn't issue receipts for paper tax returns. However if you file online you'll get an on-screen acknowledgment once they've received your return.
If HMRC receives your tax return after the filing deadline, you'll be charged an automatic £100 penalty.
If a Partnership Tax Return is late there's a £100 penalty for each partner.
If a Trust and Estate Tax Return is late there's a £100 charge to the trust or estate.
You won't have to pay a penalty if you have a reasonable excuse for missing the deadline. There's no hard and fast rule on this but usually the delay must be completely due to an exceptional or major unexpected event that's outside your control.
Some examples of what HMRC may consider as a reasonable excuse are:
If you've got a reasonable excuse you can ask for a penalty to be reconsidered. HMRC will look carefully at the information you provide and any other evidence that's available. You should make any claim as soon as possible - don't wait until you receive the penalty.
To make a claim, write to your Tax Office and give the following details:
What counts as reasonable excuse for filing your online return late – find out more
It's expected that there will be changes to how penalties work for the 2010-11 tax return. This will affect late tax returns from October 2011 onwards.
Read more about Self Assessment penalties from October 2011
If you don't send in your return on time HMRC may decide to estimate the tax due and request payment. This is called 'a determination'. Because your payment will be late, you'll also be asked to pay interest on the estimated tax due. You can only change the amount of the estimate by sending in your completed tax return.
You'll also have to pay a late filing penalty - and there may be further penalties if you still don't send your return in.
You must pay any amount due by 31 January following the end of the tax year. For example, for the tax year 2009-10 (ending on 5 April 2010) you must pay any tax due by 31 January 2011. The payment deadline is the same whether you file on paper or online.
You'll need to pay one or both of the following:
You'll usually receive a 'Self Assessment Statement' that shows the amount due. If you don't receive this before payment is due, you'll need to work out the tax due yourself using your tax calculation and previous statements or by registering for Self Assessment Online and using the 'View Account' option.
Your Self Assessment Statement - find out more
If you've been asked to make payments on account, this is the deadline for making your second payment on account'
For example on 31 July 2011, you'd make your second payment on account for the 2010-11 tax year.
If you pay your tax late HMRC will charge interest from the date the tax was due until your payment is received.
If you still haven't paid your balancing payment (due on the 31 January) by 28 February, you may be charged a 5 per cent additional charge, called a surcharge, on top of the amount you still owe. This is in addition to any interest you've been asked to pay.
If you still haven't paid all of the tax due on 31 January by 31 July, you may be charged a second 5 per cent surcharge on top of the amount you still owe.
It's expected that there will be changes to how late payment penalties work for the 2010-11 tax return. This will affect payments due on or after 31 January 2012 that are paid late.
Read more about changes to Self Assessment penalties for the 2010-11 return
