If you’re filing a tax return, avoid these top 5 Self Assessment mistakes to save money and stay compliant.
Top 5 Self Assessment Mistakes
1. Missing the Deadline
Self Assessment deadlines are:
- 31 January – for filing online returns and paying any tax owed
- 31 July – for the second payment on account (if applicable)
Late filing = £100 fine (even if no tax is due).
2. Not Reporting All Income
You must include all sources of income:
- Self-employment
- Property rental
- Dividends and savings
- Side hustles
Missing income can trigger penalties or HMRC investigations.
3. Claiming Ineligible Expenses
Only claim expenses that are wholly and exclusively for your business.
Common errors:
- Personal travel
- Clothing (unless it’s a uniform)
- Meals not related to work
4. Forgetting to Make Payments on Account
If your tax bill is over £1,000, HMRC usually asks for payments on account for the next tax year.
Missing these leads to interest and penalties.
5. Doing It All Yourself Without Advice
Self Assessment can be tricky—especially with changes like MTD coming.
A professional can help:
- Maximise allowances
- Reduce your tax bill
- Avoid errors
- Save time and stress
Need Help with Self Assessment?
I’ve helped hundreds of people file accurate tax returns on time, save money and avoid penalties.
📞 Call: 07867 410938
📧 Email: ross@moorefinancialmanagement.wales
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Mistakes can be costly.
As can missing deadlines.
