Self-Assessment Tax Returns

Self-assessment tax returns are completed by individuals and run for the financial year, 6 April to 5 April.

If you are required to complete a self-assessment tax return then the filing deadline is 31st October following the end of the tax year for a paper filing or 31st January for an electronic filing.


If your return is late then you will be issued with a £100 penalty. Once your return is 3 months late, HMRC have the power to begin issuing daily penalties of £10 per day up to a maximum of 90 days (£900). Once the return is 6 months and 12 months late a further penalty is issued being the greater of £300 and 5% of the tax due. Penalties can be appealed if you have a reasonable excuse.

If your tax return shows that you have unpaid tax then this must be paid on or before 31st January following the tax year.


If payment is late then HMRC will charge interest and further penalties. If your payment is 30 days late then a penalty of 5% of the amount unpaid is levied. Further 5% penalties are issued at 6 months and 12 months.