The way you fill out the W-4 form that you turn in to your employer determines how much tax you will have withheld from each paycheck, which determines how much you will ultimately owe or be refunded in April. Use the federal tax calculator to calculate you taxes. After your taxes have been calculated, it’s time for a review. It does make more sense to use the withholding calculator provided by the online tax software company you use to prepare and file your taxes because all of your information is already entered. The calculators are easy to use and we’ll solve your problems in a very short period of time.