If you are self employed, you will need to notify HM Revenue and Customs who will send you a self-assessment tax return at the end of the financial year. The self-assessment process provides a mechanism for calculation of any tax, National Insurance and Student Loan repayment deductions.
If you choose to calculate yourself, you will need to complete a self-assessment form and return it with any payment by 31 January following the relevant tax year. HMRC will do the calculations for you if you send in your tax return before 30 September.
