1. Overview

To send your Self Assessment tax return online, you can either:

  • use the HM Revenue and Customs (HMRC) free Self Assessment Online service
  • buy commercially available software

What you need

You’ll need an online account with HMRC.

To sign up if you don’t already have one, you’ll need your 10-digit Unique Taxpayer Reference (UTR). HMRC send you this when you register for Self Assessment. It’s also on letters or payslips from them.

Deadlines

There are deadlines for sending your Self Assessment tax return and paying any money you owe.

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