Bik company car help

Gmac1987

Hello, 

I start a new job soon and receive a company car but do jot have the option for car allowance (cash). I have been looking at cars and looking at skoda superb estate at £29320. 36% of this for co2 bringing the price to £10484. 
On the basic spreadsheet I have from employer it gives a lots of information including the rate I would pay per month for the bik, however I just want to understand what my take home pay would be every month so I can budget other things but can't find a suitable online calculator 
My base salary is 45k and I make pension contribution of 5%. Does the bik get deducted before tax deduction or after? If someone could give me a breakdown that would be fantastic. 

Thanks 

Gmac1987

Sorry, I should also have said I live in Scotland