Tax agents: key tax deadlines 2016 to 2017

For information on the key tax deadlines please visit;

Self Assessment

31 July 2017 – deadline for your second Self-Assessment payment on account for tax year ended 5 April 2017.

31 January 2018 – deadline for online Self Assessment return for tax year ended 5 April 2017. This is also the deadline for paying all remaining Self-Assessment taxes due for tax year ended 5 April 2017 and making your first payment on account for the tax year ending 5 April 2018.


To find your exact VAT return and payment deadline, enter your accounting period and preferred payment method into HMRC’s VAT deadline calculator.

Corporation Tax

If your taxable profits are less than £1.5 million, your Corporation Tax deadline will normally be 9 months and 1 day from the end of your accounting period. This applies after your first year of trading as the deadline for your first return can sometimes be slightly sooner. You’ll receive notification from HMRC when your Corporation Tax is due.

The end of your accounting period is normally the month end of the anniversary of your incorporation.

If you’ve made more than £1.5 million in profits, you’ll have to pay your Corporation Tax in instalments. Assuming your company has a 12 month accounting period, your instalment dates will be:

  • 6 months and 13 days after the first day of your accounting period
  • 3 months after your first instalment
  • 3 months after your second instalment
  • 3 months and 14 days after the last day of your accounting period