National Insurance on Bonuses

Hi, As I understand it if I am in the basic rate tax bracket I pay 20% income tax and 12% NI, however if one month I receive a bonus which puts me over £4189 for that month, I pay 40% tax and 2% NI on everything above that. Assuming overall for the year I am still paid less than £50270, I then pay less income tax the following months to ensure that by the end of the tax year I've only paid 20% income tax. But as NI contributions are calculated monthly, not yearly, I don't pay any extra NI? Would I be correct in saying that the month I receive my bonus, everything I earn over £4189 I end up paying a combined income tax and NI of just 22%?

Hi Mracapulet
Advise on the national insurance question:
National insurance is taken as and when you are paid. Please use the national insurance calculator on gov.uk for the 2024/25 tax year and the rates and tables that apply:
National Insurance rates and categories: Contribution rates - GOV.UK (www.gov.uk)
Work out an employee's National Insurance contributions - GOV.UK (www.gov.uk)
I have added the tax calculator link below but you may wish to ask the PAYE taxes question to that line of business.
Please also see the tax calculator - Work out an employee's Income Tax - GOV.UK (www.gov.uk)
Thank you.