Windows, how to convert batch program output of bytes to KB, MB or GB?

In windows batch, How to convert Bytes to KB or MB or GB?
In batch, How to output results to screen?

Below is a Windows batch that outputs a folder size in bytes.
example:
2,041,737,167 bytes in d:\temp

@echo off    set bytes=    for /f "usebackq tokens=1,2,3,4" %%a in (`dir /s/w/c "d:\temp\" ^| findstr "File(s)"`) do set bytes=%%c    echo %bytes%  bytes in d:\temp\*.*    pause    

In batch, how to convert?
2,041,737,167 bytes to:

1,993,883 KB (2,041,737,167 / 1024)
1947 MB (2,041,737,167 / 1048576)
1.9 GB (2,041,737,167 / 1073741824)

--