Personal and commercial tax – Important deadlines

Running your own business can be an empowering and fulfilling alternative to financially restricting traditional employment. But not everything in life is perfect, and the unavoidable grey lining to the entrepreneurial silver cloud is dealing with complex tax matters – with many pressing deadlines.

So let’s make it simple – here are the upcoming dates you’ll need to take note of for the financial year of April 2017 to April 2018.


31 July 2017 – deadline for your second Self-Assessment payment on account for tax year ended 5 April 2017.
31 October 2017 (midnight) – deadline for paper Self-Assessment return for tax year ended 5 April 2017.
31 January 2018 – deadline for the online completion of your Self-Assessment return for tax year ended 5 April 2017. This date is also the deadline for paying any outstanding taxes for the year ending 5 April 2017, as well as for paying your first contribution on account for the next tax year, ending 5 April 2018.

PAYE and Class 1 National Insurance (NI)

If you make monthly payments…

For the tax month ending
5 May
5 June
5 July
5 August
5 September
5 October
5 November
5 December
5 January
5 February
5 March
5 April

Funds to clear at HMRC by
22 May
22 June
22 July
22 August
22 September
22 October
22 November
22 December
22 January
22 February
22 March
22 April

If you make quarterly payments…

For tax quarter ending
5 October
5 January
5 April
2 July

Funds to clear at HMRC by
22 October
22 January
22 April
22 July

VAT payments are made every quarter, however the exact deadline will depend on when you originally registered for VAT, which in turn would have been based on when your accounting periods begin and end.

Corporation Tax
Where your profits are under £1.5 million, the corporation tax deadline will typically be 9 months and 1 day following the end of your accounting period. This deadline will be in place following your first year trading, as your first deadline may be slightly before this. HMRC will contact you to notify you as to when your corporation tax is due.

The end of the accounting period for corporation tax is typically the month end on the anniversary of incorporation.

Where you’ve made over £1.5 million in profit, your corporation tax will be paid in instalments as follows:

  • 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

At Hammonds Accountants, we remove the weight of ever looming tax deadlines and paperwork from your shoulders – allowing you to concentrate on the more important things in life, such as growing your business or spending time off with your family. Speak with us about how we can help with your tax matters – saving you time and money in the process. Call our team on 0203 007 4990, or send us a message by email and we’ll be right back in touch: .