What happens if you don't pay self-employment tax?

Missing your self-employment tax deadline

If you miss the deadline for submitting and paying your self assessment, you may have to pay a penalty.

If your self assessment return is late by:

• 1 day - you will pay a £100 late filing penalty
• 3 months - you may have to pay a penalty of £10 a day, for a maximum of 90 days (£900)
• 6 months - you’ll have to pay a further penalty of 5% of the tax you owe or £300, whichever is greater
• 12 months - you’ll have to pay a further penalty of 5% of the tax you owe or £300, whichever is greater. In some cases, you may have to pay a penalty of up to 100% of the tax you owe.

How much is a late payment penalty for self assessment tax?

As well as penalties for late filing, there are penalties for late payment of self assessment tax. You need to pay any tax you owe by 31 January following the end of the tax year.

If you are late paying your tax by:

• 30 days – you’ll have to pay 5% of the tax you owe at that date
• 6 months – you’ll have to pay a further penalty of 5% of the tax you owe at that date
• 12 months – you’ll have to pay a further penalty of 5% of the tax you owe at that date

Self assessment late payment penalties are in addition to any late filing penalty. Find out more about self assessment penalties here.

When MTD for ITSA comes into place, self-employed people will be subject to the new points-based penalty system instead.