This page can be found on the web at the following url: http%3A%2F%2Fapps%2Eopm%2Egov%2Ftax%5Fcalc%2Findex%2Ecfm
Read about how the tax-free part of your annuity is determined.
Figure your monthly federal income tax withholding
Please contact us at retire@opm.gov for information or assistance.