August 6, 2019 The Tax Withholding Estimator helps make it easier for everyone to pay the correct amount of tax each year. This tool can help you tailor the amount of tax you have withheld from your income during the year and avoid surprises at tax time. New features now provide more accurate estimates of withholding if you have a regular paycheck and self-employment income. These features include the ability to: calculate tax on your self-employment income. see if you qualify for adjustments for self-employment insurance or contributions to qualified retirement plans.