It's not quite as straight forward as that.
As tax due is calculated on a cumulative basis throughout the tax year,
the process is as follows:
First you need to calculate your taxable pay for the year to date. This is
done by taking the Free Pay for the current period as defined by your tax
code, from the total pay to date including the current period. You then
calculate the tax due on that amount. Subtract the tax you have paid up to
and including the last period, and that is the tax due for this current
period.

National Insurance IS a straight forward percentage of the period gross
pay, but you need to split it between Emploees Contribution and Employers
Contribution.

Have you got a set of Tax Tables?


Right, thats useful. Cheers. No I dont have any tables. Do you have a link
as to where to obtain one?

thanks for the reply