I don't understand the Loss section in my Self Employment Tax Return? Help! UK ONLY!?

In simple terms, a business loss is where the expenditure you make in relation to the business (stock, advertising etc) exceeds the income from the business.

Have a look at www.businesslink.gov.uk for lots of useful advise - or the HRMC website. Both offer free courses which you would probably find valuable.

Making less than you want, or you have before, is not a loss.

A loss is profit of less than zero pounds. In simple terms you calculate your profit by taking your total income, then deducting allowable expenses, then deducting capital allowances. For example:

If your total income was £30,000 and you expenses were £15,000 and your capital allowances were £2,000 you have a profit of £13,000. But if your income was only £12,000 with the same deductions your profit would have been -£5,000 (ie minus £5,000) which is a loss of £5,000.

This section of the form is not asking for "new" information, but it is an area where you are carrying forward information from elsewhere on the form. If you have not made a loss then you can ignore the loss section of the form. If you have made a loss you are entitled to use it to offset against other income in the same year, or you can carry it forward to offset against your profits in future years.

EG, if you also had a job (or income from shares or property) in 2009/10 you will have had "other income" and you will be liable for tax on this income as well. If you earned £15,000 from the job you could deduct your loss to leave you with a balance of £10,000 on which tax is due.

Its too late to register for this year, but if you do the return online all these things are sorted out for you. All you need to do is enter the information once.