What is a good resource for adjusting my BASD?

Go to your local active duty Career Counselor. We spend two months of school doing nothing but calculating timelines, BASD/PEBD and DIEMS for 8 hours a day all week for our basic course.

Sir, I would get with your S1, they should have that calculator that figures out your PEBD date. Also, get with HRC and make sure your NGB 32 reflects your AD time. We have to adjustments for when Guard comes over to Reserve or even Active to Reserve. I had to have my S1 do it for myself coming from Active.

If you are currently RA, this should have happened at your transfer.

Last time I had it adjusted it was done on DA form 1506; AR 37-104-3 the controlling reference. Keep in mind drills do not count toward regular retirement eligibility or BASD; they only get counted toward your compensation.

edit: forgot to write the form number: DA 1506