Calculate your after-tax bonus. Choose flat (22%) or aggregate method to see federal, state, SS, Medicare deductions and net bonus.
Flat method withholds 22% federal on the bonus. Aggregate adds bonus to regular pay and calculates tax on the total, which may result in higher withholding for high earners.
If too much was withheld, the excess is returned as a tax refund when you file. The withholding method doesn't change your actual tax liability.