Filling in your tax return – 5 mistakes to avoid

Leaving your tax return to the last minute means you are more likely to do it in a hurry and therefore more likely to make careless errors.  Filling in your tax return online is a good way of avoiding mistakes because calculations are done automatically and there is on-screen help if you need it, says the Revenue. But it is still easy to trip up, due to carelessness, not being organised enough, or lack of knowledge. Here are the five most common errors:

Don’t leave things out

Probably the most common mistake of all is the omission of a source of income, typically the interest arising from a bank or building society account, which in some cases can be quite substantial. So before you start, gather together the documents relating to all your savings accounts and investments – statements, passbooks etc.

You have to include the interest you receive on bank, building society and other savings accounts, and on any loans to individuals or organisations.  You don’t have to declare interest from Isas.

You must also include dividends from UK companies and unit trusts, open-ended investment companies and investment trusts.

Don’t get your numbers in a twist

Another common error is, say, including the gross amount of interest instead of the net amount after tax that is being asked for.

For example, with box 1 on page TR 3, relating to taxed UK interest, you need to put in the net amount – the interest etc after tax was taken off. Some account statements will explicitly give this figure; others just show gross interest and tax taken off.

Get your tax code right

Now’s the time to check. Thousands of taxpayers may well be paying too much (or too little) tax as a result of having the wrong tax code.

In some cases people have received refunds running into thousands of pounds after belatedly spotting that they have been paying too much for years.

Your tax code can usually be found on your payslip – it’s typically three digits followed by an L, such as “744L”, and it tells your employer how much to deduct from your pay packet.

If your employer provides you with company benefits, such as medical insurance or a car, you will probably have to pay tax on them.

To check you’re on the right tax code, try’s online code checker.

Don’t forget gift aid

You can tell the taxman about donations by filling in the section “gift aid payments”. Gift aid boosts the value of donations by allowing charities to reclaim basic rate tax on your gift: £10 using gift aid is worth £12.50 to the charity.

If you pay higher-rate tax, you can claim extra relief on your donations. For example, if you donated £100 using gift aid, the total value of your donation to the charity was £125 – so you can claim back £25 if you pay tax at 40%, or £37.50 if you pay tax at 50%.

When you’re asked about gift aid payments made in the year to 5 April 2012, enter the actual amounts given – don’t add on any tax relief that you think the charity will obtain.

Don’t forget to pay what you owe! 

As well as pressing the button to send your form, you must pay what you owe by 31 January – this applies whether you filed a paper or online return.

Coalesco still have capacity to assist those taxpayers concerned about the deadline – please get in touch if you need help filling in your tax return.