How to calculate the penalty for a w4 withholding | ehow, How to calculate the penalty for a w4 withholding. claims you make on form w-4 tell your employer how much income tax to withhold from your pay. your employer is not. How to figure out the tax withholding percentage | ehow, How to figure out the tax withholding percentage. employers are required to withhold federal, and in most cases, state taxes from employees' wages. federal taxes. How to fill out form w-4, employee's withholding allowance, How to fill out form w-4 tips for preparing the employee's withholding allowance certificate in 11 steps.