How do you calculate withholding tax for bonus?

Panwa: Please note that Bonus is considered as income derived from employment in according to the Revenue Code. Thus, calculation of the personal withholding tax must include bonus with the other assessable income derived from employment under the Revenue Code Section 40 (1) and (2). It unable to separately calculate the withholding tax.

The net assessable income after deduction the standard expenses and allowances according to such law will calculate and deduct the withholding tax follow the personal income tax rates.