RMD Federal withholding tax percentage

[BJ-CiCi]

I'm 5 years retired and over 72. I found a formula to know what tax bracket I'm in. I found a formula to know what amount of RMD I need to take each year. I cannot find a formula that tells me what percentage needs to be withheld for federal taxes from the RMD that I take in a lump sum each October. The custodian (not past employer)  of my RMD funds doesn't offer advice on this and says it is up to me to decide. I chose 10%, but won't know until taxes are filed if it is too much or too little. Is there a formula for this? 

[carmen_t]

Great work in finding those formulas.  To further answer your question and provide you with a useful tool.  I would use a tax estimator to give you an estimate of your overall taxes and how your position will look.  This will help you to get a closer percentage for RMD withholdings.  

Refund Estimator