Remember: it's tax time again

Dig out those Revenue forms now if you can't face doing the sums alone

September is an important month for taxpayers. If you are one of the 9 million people who have been sent a self-assessment form and don't want the hassle of calculating how much tax you have to pay, the Inland Revenue will work it out for you - as long as you return the form by 30 September.

September is an important month for taxpayers. If you are one of the 9 million people who have been sent a self-assessment form and don't want the hassle of calculating how much tax you have to pay, the Inland Revenue will work it out for you - as long as you return the form by 30 September.

However, this month the deadline falls on a Saturday so you would do well to get your form in by Friday 29 September. Even though you won't be fined if you don't send your form in before this date, life will be a lot easier as you won't have to calculate the tax you owe.

The absolute deadline for returning your form if you want to avoid a fine is 31 January 2001: if you are aiming for this date, you will have to calculate your own tax.

Taxpayers may prefer to work out their own payments anyway, given the problems the Revenue has encountered with its computer systems, and the number of mistakes it has made in calculating people's tax liabilities. But tax experts believe it is still better to get the Revenue to make the calculations than trying to work it out for yourself.

"We are beginning to hear people claiming that taxpayers would be best advised to do their own calculations because of Revenue errors," says Sharon Linnard, tax partner at KPMG. "I think that is bad advice. While, of course, people should check the Revenue's figures, there are many advantages in getting the return in by the end of the month."

If you do get your form in before the end of the month, the tax office will calculate your liability and let you know what tax you need to pay before 31 January 2001. If the tax due is less than £1,000 and collected through pay-as-you-earn or PAYE, the tax office will include this in your tax code for the 2001-02 tax year.

If you prefer to make the calculation yourself, you must pay the tax due on or before 31 January. If it is less than £1,000, it will probably be too late to include in your tax code by then, so the tax will be payable as a lump sum by 31 January.

However, if you are intending to send off your form before 29 September, you need to act now. Dig out the form and get all the paperwork you need.

"Treat the return like an exam paper - read every question carefully and give the answers the Revenue needs, not the ones you would like them to have," says John Whiting, tax partner at PriceWaterhouseCoopers. "The copy of last year's tax return (we recommend you take a copy) is a useful starting point and should help to make sure you don't forget anything obvious."

The Inland Revene provides a number of easy steps to follow to ensure you fill out the form correctly:

* The second page of the return will tell you which supplementary pages you need to complete. The self-employed, those in employment or in receipt of rental income, will need to complete supplementary pages. These should be ordered now from the Revenue if they were not sent with the tax return.

* Gather together all primary documents detailing income, gains, and tax deducted for the year 6 April 1999 to 5 April 2000 (see box). You will have to disclose income even if it has been taxed at source.

* Write clearly in the boxes. Don't attach anything to the tax return, such as your P60, as the Revenue will not look at these when processing returns and documents may not be returned.

* Don't forget to sign and date the tax return - not doing so is the most common error.

* Attempt to calculate your tax liability to give yourself a rough idea of what to expect from the Revenue's calculations.

If your affairs are complicated, it is worth seeking professional advice. If the Revenue or its website can't help, (see Online Oracle, opposite) ask a professional tax adviser.

* Inland Revenue self-assessment order line 0645 000404; or www.inlandrevenue.gov.uk