One of the best features of the FEHB program is that almost all employees can carry the coverage into retirement, the premiums you’ll pay in retirement are identical to the ones you’d pay as an employee. The premiums would be deducted from your monthly annuity payments rather than your bi-weekly pay. So, if you want to know what your monthly payment as a retiree would be, multiply your bi-weekly rate by 26 and then divide by 12.
However, the premiums will effectively cost you more in retirement, though, because retirees aren’t eligible for to pay FEHB premiums with pre-tax money under the “premium conversion” arrangement that applies to active employees. Almost all active employees choose to pay premiums that way—you can elect not to, but there are only limited situations, typically involving very low-income employees who pay no federal income tax, where that makes sense.
There is a limited exception for retired firefighters and law enforcement officers to pay premiums pre-tax. They should check with their tax advisers regarding that benefit.