Estimated tax is the method used to pay Social Security and Medicare taxes and income tax, because you do not have an employer withholding these taxes for you. Form 1040-ES, Estimated Tax for Individuals (PDF), is used to figure these taxes. Form 1040-ES contains a worksheet that is similar to Form 1040. You will need your prior year’s annual tax return in order to fill out Form 1040-ES.
Use the worksheet found in Form 1040-ES, Estimated Tax for Individuals to find out if you are required to file quarterly estimated tax.
Form 1040-ES also contains blank vouchers you can use when you mail your estimated tax payments or you may make your payments using the Electronic Federal Tax Payment System (EFTPS). If this is your first year being self-employed, you will need to estimate the amount of income you expect to earn for the year. If you estimated your earnings too high, simply complete another Form 1040-ES worksheet to refigure your estimated tax for the next quarter. If you estimated your earnings too low, again complete another Form 1040-ES worksheet to recalculate your estimated taxes for the next quarter.
See the Estimated Taxes page for more information. The Self-Employment Tax page has more information on Social Security and Medicare taxes.