I know i could get the answer to this elsewhere, but you guys are so knowledgeable.....
Im a full-time PhD student, but if i earn more than the tax benchmark per annum (i think its currently £5000-something), does everything you earn get taxed, or just anything you earn over that benchmark ammount?
Cheers!

The basic allowance for 2006/07 tax year is £5035. This is not taxed. The next £2150 will be taxed at 10%, and the next £2151 to £32,300 at 22%. Bear in mind that any stipend you recieve for your PhD will normally be tax free and not included in these allowances. Such awards are effectively invisble to the taxman.

This may be different if you circumstances allow you to claim any tax credits. You may also have to pay national insurance contributions. Check out www.hmrc.gov.uk for more detailed info.

Not necessarily - I was taxed as a full time student

jcgrant31 that is not correct. Full time students are exempt from paying council tax, but not income tax. Students pay income tax at exactly the same rate a non-students in the way that mc2006 says, so if you earn 20 grand a year you will be taxed on roughly £15,000 at 22%.

The key thing to note is that bursaries are not taxed, but salaries are, even if you are a full-time student. I did my PhD as a salaried research assistant and paid the normal rate of tax on my monthly earnings (bah!)

It doesnt matter if you are a student, a full time worker or a highly trained baboon, it is being an employee that counts. If you are employed then any income (above the limits mc2006 gave) is liable for income tax.

I dont see how you can NOT be paying tax on earned income - anything I have earnt has had tax deducted before I saw any of it. If anyone really is not paying tax on earnings then watch out, the inland revenue will catch up with you sooner or later.

jcgrant31: When you say earn over £12k, how do they earn this? As everyone has pointed out, if this is earned income (i.e. from a job they do in addition to their PhD and not from a stipend or bursary etc) then it will be subject to income tax and national insurance contributions. They and their employers could be commiting a serious offence by not paying tax or NI.

Your funding from the research council (~£12000) is tax free, but any other earnings from tutoring/demonstrating or part-time work will be taxed in the same way as someone in full time employment - ie anything in the year earned over your tax allowance (~£5000 per year i think) will then be subject to income tax

Your stipend is usually tax free (what you get paid for doing a phd from reaserch council). Any other work (eg bar or shop work) is taxed. However, if you are a full time student you will probably be unlikely to reach the first tax limit (£5000 ish), and can claim all of that tax back (including I beleive tax on interest on bank accounts). Additonally, your funding body probably limits the amount of extra work you can do, so again it seems unlikely that you would go over the min amount.

So in effect, for tax purposes, it is like you were never earning your stipend. It doesnt count towards your tax bill, so you get 5000 on top of that tax free.

If you are self funded, then I guess you would pay tax the same as every non student. Thats how i understand it anyway.