Self Assessment: the most common mistakes when filing a tax return

When filing a Self Assessment in the UK, many taxpayers make mistakes that can lead to penalties from HMRC. The most common issue is late registration, when a person is effectively self-employed but does not register and submit a tax return on time and hence incurs late registration penalty

Another frequent problem is incorrect reporting of income. People often fail to include all sources of earnings or incorrectly claim expenses, which affects the final tax calculation.

Many also miss filing or payment deadlines, which automatically results in penalties. To avoid issues, it is important to keep accurate records throughout the year and submit your tax return on time.