Tax Zone >> Tax Helpsheets >> Self Assessment

An Introduction to Self-Assessment

The tax year runs from 6th April to 5th April in the following year and under self-assessment it is up to the individual taxpayer to calculate their own tax liability and pay the tax due by the due date

Who has to fill in a Self-Assessment Return?

The majority of people in the UK are taxed under PAYE and do not have to complete a Self Assessment tax return. However, where you have income that is not taxed at source or may be liable to higher rate tax on income that has only had basic rate tax stopped you will probably need to complete a self-assessment return. It is your responsibility to notify chargeability to tax to HMRC

The following people usually have to complete one...

If you are unsure whether you need to complete one, please contact us for advice

Filing the Self-Assessment Return:

Self-Assessment returns are issued in April

Paper returns have to be filed by 31 October following the end of the tax year and HMRC will calculate your liability for you. For online returns you have until 31 January following the end of the tax year to file the return. If you file the tax return online through the HMRC website or through an accountant , the tax liability will be calculated for you

If the return isn't filed by the due date, there is an automatic fine of £100, which is reduced to the level of tax due if that is less. There is a further £100 fine if your return is still outstanding six months later

Due Dates of Payment:

The method of payment usually involves two payments on account of your tax liability as follows...

These are based on the net income tax and Class 4 NIC liability of the previous tax year

A final payment (or repayment) is due on 31 January following the tax year

Thereafter, there is a 5% surcharge on any taxes that remain unpaid after 28 February, and a further 5% on taxes not paid after 31 July