In the simplest case, if you are single and withdraw $25,000 or less from the IRA, then your social security is tax-free and you will pay about 6% federal income tax on the IRA. (No tax on the standard deduction of $12,500, then 10% on the next $9000, then 12% on the last $6000.)
However, if you are married, or have other income, or withdraw more than $25,000, then your tax on the IRA goes up and you also start to pay tax on your social security. So you really need to use one of the online calculators.
