@Cheflibby , It is not taxable. When you start the tax return, it assumes you did not get any credit and give you the full stimulus amount. As you proceed with your return and in the end, where it asks you how much you received as stated on Letter 6475 and you enter the information, since you now state you already got the stimulus payment, it removes the credit it gave you initially when you started the return.
Recovery Rebate Credit is on Line 30 of Form 1040.
