My answer specifically answered the question that you asked. As I said, if no specific direction by the recipient is made, the law requires all IRA custodians to withhold 10% for federal taxes. However, the the law also allows for recipient to specifically ask that either no taxes be withheld or that any amount over 10% be withheld. (Financial institutions generally limit that choice to be whole percentage points between 11% and 99%.) In other words, it's entirely up to the recipient whether 0%, 10% or some amount greater than 10% is withheld. Tax withholding simply adds to the recipient's tax withholding from other sources and is credited on the recipient's tax return against the recipient's overall tax liability.
The actual tax liability resulting from an IRA distribution is not determined until the recipient's tax return is prepared. The advantage of having of taxes withheld is that it will reduce or eliminate an underpayment penalty that would otherwise be due for having too little withheld or too little separately paid in estimated taxes (via Form 1040-ES) during each of the tax quarters throughout the year.
