Same rate as their regular earnings.

You pay the same rate of taxes out of your bonus as you would your usual earnings.

You pay whatever tax rate applies when you file, but employers typically withhold a higher percentage, somewhere in the area of 40-45% when giving a bonus. I think this is mandated by the gov't with the idea of not causing the employee to have a large tax bill when it comes time to file. Better to get it back at the end of the year than to have to come up with a large sum. At least this is the only reason I can think to tax it this way.

Taxes on bonus's are differnt than you regular wage tax, and vary from state to state, other factors such as your projected yearly income also come into play. To find out how much you should pay for a particular bonus, use this simple calculator.

http://www.payroll-taxes.com/calculators-link.htm

It is the same rate as any other pay you would receive.