How is time in service and time in grade calculated when moving between Guard/Reserves and active duty?

I need some guidance and clarification.

I served in the Army Reserve from April 2011 to January 2016. In January 2016, I switched to the National Guard to join a Special Forces unit. I was in the National Guard from January 2016 to July 2018. In July 2018, I switched to back to the Army Reserves, and joined a PSYOP unit.

I transferred from the Army Reserve on, 7 September 2021 to the Regular Active Army.

Recently, I was told that my time-in-service reset as well as my time-in-grade.When I went on active duty. That they would both be my Basic active service date.


Is this correct? I have read the regulations AR 600-20 and AR Regulation 600–8–19.

I’m AR 600–8-19, states pretty clear that:

1–15. Computing time in grade and service

“Compute TIG and TIS in accordance with applicable regulations. Basic active service date (BASD) is used to determine TIS for RA Soldiers; PEBD is used for USAR and ARNG, regardless of RC duty status (traditional, military technician (MT), or AGR).”


I does anyone else have experience with this?

I am still confused by the TIG. I have been told it doesn’t change, that it does complete reset to my first day of active duty and that my previous and current TIG counts?