iKnowTax.com allows you to calculate how much income Tax and National Insurance you pay.
You can enter your earning/salary in yearly, monthly, weekly or hourly.
It calculates fast as you type in your earning.
It shows a breakdown of your earnings clearly in a table showing you how much Tax paid, deductions for National Insurance, how much Personal Allowance you have, total deduction and how much you take home after all the deductions. It displays in columns showing for yearly, monthly, weekly and hourly.
One unique feature it has is; it allows you to enter how many hours you work weekly to display your hourly calculations accurately.
It also shows how much you took home last year, so you can compare and see easily.
Also, iknowtax.com allows you to learn and understand how Tax and NI is calculated on your earning and applied. It provides examples of the calculation. It aims to make a complete beginner understand how tax is calculated.