How is my tax calculated?

Hi, Im currently looking at my finances in preparation for buying a house. I've been looking at various websites such as Revenue, AAM to get a better understanding of taxes. Im a bit confused about one thing though - I have a basic salary but i earn about E10k more than that so my wages vary each pay check depending on the shifts i work (Im working in the HSE). My question is how is my tax calculated each time if my pay varies? Am i automatically taxed at the lower tax bracket until I hit the cut off point during the year (Jan-Aug for example) and then everything after that is at 41% for the rest of the year (then Sept- Dec)? Im just wondering because after going over old pay checks for the last 2 years i cant see any difference throughout the year.
This might be a silly question but im fairly confused at the mo after reading so much so thanks for any replies!!

Your cut off point is split into monthly figures and accumulates month by month.

Tour tax in any month is calculated on an accumulated basis, i.e. your pay for the year to date less credits YTD and your cut-off-point YTD.

The tax you had paid up to the prevoius month is then deducted to arrive at yout tax for the month in question.

This method is designed to spread your tax evenly over the year so you do not get hammered at the back end of the year.

Hi gerpug,

I wrote a spreadsheet which might help you to calculate your monthly/ fortnightly pay. It's available at taxcalc.eu/monthlyss. (You might find it a little detailed to use but if you have a payslip I can talk you through how to fill it in.)

If you are interested, you can download it and send me either a PM here (or use the email shown on the spreadsheet). I can guide you through the steps for filling it in. You'll be able to see the net pay each month based on your personal circumstances.

Brian