The Potongan Cukai Bulanan (PCB, a.k.a. Scheduled Monthly Tax Deduction) calculation for bonus is not so straight forward.
Here is how it will be calculated.
Assuming you are not married, your monthly salary is RM4,000, you are contributing 11% from your salary to your EPF savings, and you received 2 months bonus in January 2010.
Salary = RM4,000
EPF deduction = RM440 (maximum total EPF deduction allowed for
PCB calculation is only RM500, therefore available balance left is RM500
- RM440 = RM60)
Salary to calculate PCB
= Gross salary - EPF deduction
= RM4,000 - RM440
= RM3,560
PCB 2010 according to table for RM3,560 = RM87
2 months bonus = RM8,000
EPF deduction = RM880
Maximum available EPF deduction for PCB calculation = RM500 - RM440 = RM60
Therefore, the EPF deduction should be RM60 instead of RM880
Bonus to calculate PCB
= Gross bonus - EPF deduction left
= RM8,000 - RM60
= RM7,940
The amount for bonus PCB calculation has a formula like this:
(1/12 x net_bonus) + net_salary
Therefore, amount
= (1/12 x RM7,940) + RM3,560
= RM4,221.67
PCB 2010 according to table for RM4,221.67 = RM194
PCB for bonus = (RM194 - RM87) x 12 = RM1,284
Total PCB for the month
= PCB for salary + PCB for bonus
= RM87 + RM1,284
= RM1,371
Therefore, for the month with bonus:
Gross salary+bonus = RM12,000
EPF contribution from employee @ 11% = RM1,320
EPF contribution from employer @ 12% = RM1,440
SOCSO contribution from employee = RM14.75
SOCSO contribution from employer = RM51.65
PCB deduction = RM1,371
Amount you'll get = RM12,000 - RM1,371 - RM14.75 - RM1,320 = RM9,294.25