wrote:
I know how to calculate cagr though can someone please let me know if
this seems right for cagr with a six month lag?
((January 1, 1992 Value/July 1, 1991)^2)-1)*100
For some reason this has not been working for me...

Using your notation, try:

( ( (July 1 1992 value) / (January 1 1992 value) )^2 - 1 ) * 100

Note that you do not need "*100" if you are writing an Excel formula.
Simply format as Percentage with 2 decimal places, if you want (Format
Cells Number).