Should i pay all my pension and social security taxes using funds from my ira

[StanM1]

I'm 73 and subject to RMD. Is there a tax advantage in paying my Federal taxes on my pension and social security income using money from my IRA funds?

[VolvoGirl]

No.  You can  use your IRA RMD and withdrawals for anything  you want.  It will still be taxable.  Doesn't matter how  you pay the taxes on all your income.  You can have withholding from your pension and social security or send in quarterly estimated payments.  Or even have it all withheld from your IRA withdrawal.  

But if you take out more from your IRA  to cover the taxes, the withdrawal will still be taxable.  

[Opus 17]

It depends on what other funds you have.  If your RMD is not enough to cover your tax bill, where else might you get the money to cover the taxes, if not by withdrawing even more from the IRA?

Assuming you have other sources of funds (such as savings account, broker account that is not in an IRA, compensation from working), then which funds you spend first is kind of complicated and depends on your long term goals, your family situation, and other factors. A withdrawal from a traditional pre-tax IRA will be fully taxable.  Cashing in other investments might be partially taxable, or even create a deductible loss, depending on your investment performance.  This all can have implications for the future, such as leaving assets to your family, or should you ever need long term medical care.  

You might want to talk to a financial planner.