The self-assessment tax return is an annual form that HMRC issue, either in paper format or to be completed online. You need to complete if, in the last tax year:
you were self-employed
you earned £2,500 or more in untaxed income, e.g. from renting out a property or savings and investments
your savings or investment income was £10,000 or more before tax;
you made profits from selling things like shares, a second home or other chargeable assets and need to pay Capital Gains Tax;
you were a company director - unless it was for a non-profit organisation (e.g. a charity) and you didn’t get any pay or benefits, like a company car;
your income (or your partner’s) was over £50,000 and one of you claimed Child Benefit;
you had income from abroad that you needed to pay tax on;
you lived abroad and had a UK income;
you got dividends from shares and you’re a higher or additional rate taxpayer;
your income was over £100,000;
you were a trustee of a trust or registered pension scheme;
you had a P800 form from HMRC saying you didn’t pay enough tax last year - and you didn’t pay what you owe through your tax code or with a voluntary payment.
This seems like a complex list and it is, if you’re not used to dealing with it! Many of our self-employed clients prefer to leave all the calculations and form-filling in our capable hands.