You can make an estimated tax payment to the IRS at any time. The IRS will gladly take your money whenever you are willing to send it.The four estimated payment schedule dates are deadlines by which you are required to pay a certain portion of your taxes or risk being liable for penalties. They are not the only times at which the IRS will accept payments. There is no penalty for paying your tax ahead of when it is due. The IRS will not blow a gasket if you make more than four estimated tax payments for a single tax year.You may make an estimated tax payment at any time by mailing a check or money order accompanied by Form 1040-ES (it doesnu2019t matter which of the four vouchers you use) to the address in the Form 1040-ES instructions, or by any of the other several methods mentioned in the Form 1040-ES instructions. Make sure you use the correct form for the appropriate tax year.Form 1040 ES, Estimated Tax for Individuals