This information is taken from workSMART.org.uk, the help and advice portal for all people at work, from the TUC.
If you would like an indication of how much tax you should be paying, you can try our online Tax Calculator.
The Inland Revenue site is very comprehensive, and has details of current rates and allowances, as well as some useful calculators for tax credits. You can find it at www.inlandrevenue.gov.uk