Traders have significant tax deadlines to meet annually. Some deadlines may change if they fall on a bank holiday or weekend. For self-assessment filing, the dates are October 31st for paper filing (if notified by HMRC), December 30th for online filing (if tax dues are less than £3000), January 31st for online filing (with government gateway sign in and password), January 31st for the first payment (50% of tax liability for the previous year), April 6th for the beginning of a new tax year (expect tax return paper if required to complete self-assessment), and July 31st for the second payment. For limited company filing, the latest date to file is 9 months from accounting period end, for example, if the accounting period is 01/01/2016 - 31/12/2016, the latest date to file is 01/10/2017.