Application of Personal Allowance to taxable salary

Good morning, I had a query on behalf of my wife's situation. She is a primary school teacher in Scotland in her 2nd year (gross pay of £40848). When looking at her taxable pay, after deducting £3300 on pension and another £3000 on NI, there's a taxable pay of £34700. Where is her personal allowance of £12500 used? If I'm not wrong, the allowance should be deducted from the taxable pay (34700-12500 = £22200), then apply the 20% tax to that amount (22200*0.8 = £17760), add that to the personal allowance (17760 + 12500 = £30260), and finally divide that amount by 12 to get monthly salary (30260/12 = £2521/month). However, the salary that gets in her account is far lower. She's only got student loan to pay, and the numbers still do not much. Am I missing something here? Many thanks, Adrián

Hi,
This forum is for general queries only and is intended to help you self-serve. We are unable to provide specific advice tailored to individual circumstances. 
You may wish to contact our Self Ateam for advice
Self Assessment: general enquiries
Alternatively you may want to seek professional advice. 
Thank you.

Hi, I believe this is a very general topic. It is true that I have included details for our specific situation but the question applies to every tax payer in the UK. Every worker has a Personal Allowance, when and how is this allowance applied? I just gave the numbers to illustritate better that I cannot see where the allowance has come in place. Best Adrian

Hi ,
 

The Personal Allowance is given through your PAYE code - for example the Personal Allowance due just now is £12,570 and this converts to a PAYE tax code of 1257L and this is applied against taxable salary - please see the following Guidance for further help - : Income Tax rates and Personal Allowances  and   :  Tax codes   . Thank you .

Thank you very much for your reply. When looking at the salary breakdown I cannot see that allowance applied. There's a gross salary labeled as "Pensionable salary", after Pension and NI paids are deducted there's then a "Taxable salary". Would the Personal Allowance be applied then?

Hi,
You are correct that the personal allowances would be deducted off gross pay, so the standard personal allowances of £12500 divided by 12 = £1041.66 per month tax free, anything over this is then taxed at the appropriate tax rates.  
If your wife is resident in Scotland your wife's income will be subject to the Scottish rates of income tax.
Please find attached a link to guidance which may help.
Income Tax in Scotland
Thank you.