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Online self assessment - top mistakes to avoid

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  • Publish date: 10 January 2017
  • Archived on: 10 January 2018

Tuesday 10 January 2017, The 31st January online self assessment deadline is quickly approaching. 823,000* left it to the eleventh hour and submitted their tax return on 30th and 31st January last year. ICAEW is reminding everyone not to delay, leave enough time to complete your self assessment properly and avoid making these classic mistakes.

Anita Monteith, Technical Tax Manager explains:

“Putting your tax return off until the last minute can lead to mistakes and you may have to pay a fine if HMRC deem you have not taken enough care in completing it. Gather all your important documents before you start, together with a copy of your previous year’s return and always check through your self assessment before submitting to avoid these common errors.”

Don’t forget charitable giving – Missing out gift aid donations is a common mistake. Make sure you have records of all your gift aid payments. If you pay tax at the higher or additional rate, you can claim tax relief for the difference between the tax rate you pay and the basic tax rate on your donations.

Remember tax on savings – Remember, if you have high levels of savings, you may have to pay tax on the interest. Until April 2016, savings providers deducted tax at 20% automatically from savings accounts, but if you are a higher rate tax payer you will have additional tax to pay. If your income is below the personal allowance of £11,100, you may be entitled to a tax repayment. You can ask your bank or building society for an interest statement.

Forgetting supplementary pages - If you have other sources of earned or investment income, you will need to include supplementary pages. This additional income may come from  investments, property, shares etc. 

Not declaring all income/Capital Gains – There are severe penalties for failing to declare all taxable income and capital gains. You’ll need to gather details of any assets you’ve sold in the year, such as shares. Don’t forget to declare your dividend receipts.

Pension contributions - Make sure you know the contributions you can and can’t claim tax relief on. You can get tax relief on most contributions you make to registered pension schemes and some overseas pensions schemes. You can’t claim relief for payments for life insurance. If you’re not sure, ask your pension scheme administrator or an ICAEW Chartered Accountant for advice.

Incorrect figures - Remember to check through your self assessment before submitting to HMRC, comparing it to last year to make sure you haven’t forgotten anything. If there have been any significant changes, it is a good idea to use the white space boxes on the tax return to explain these to save HMRC writing to ask you later if you have made a mistake.

Anita adds: “Don’t panic if you realise you have made an error on your tax return, you’ve normally got 12 months from the submission deadline to correct it. This is called an ‘amendment’. This would give you until 31st January 2018 to make a correction.


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