Browsing: civilian annuity computation

Q: I am sure that you have answered this question before — it seems so basic to me — but I could not find a comparable Q&A on your site. Here goes: I have 11 years, 2 months, 20 days of active Air Force service, no Guard or reserve (retired from Guard but I believe it’s irrelevant; no active time other than for training). I have been tentatively hired by DECA as a GS 4 (awaiting clearance paperwork). I don’t know anything about federal retirement plans, as I am not in one yet. How will the “buyback” of my time…