Timercur,
C:\>timeinseconds.bat
start time=13:24:37.71
Hour=13
minutes=24
Total Seconds in given minutes=1440
Total seconds in given Hours = 46800
seconds= 37
start time in seconds =48277
end time=13:24:47.97
End Hour=13
minutes=24
Total Seconds in given minutes=1440
Total seconds in given Hours = 46800
seconds= 47
end time in seconds =48287
Total Time used in seconds = 10
C:\>type timeinseconds.bat
@echo OFF
rem start - end time
REM time format 12:46:26.94
echo start time=%TIME%
set HH=%TIME:~0,2%
echo Hour=%HH%
set MM=%TIME:~3,2%
echo minutes=%MM%
set /a MM=%MM% * 60
echo Total Seconds in given minutes=%MM%
set /a HH=%HH% * 3600
echo Total seconds in given Hours = %HH%
set SS=%TIME:~6,2%
echo seconds= %SS%
Set /a start=%HH% + %MM% + %SS%
echo start time in seconds =%start%
echo enter time to sleep
set /p sleep=
sleep %sleep%
Rem end time in seconds
echo end time=%TIME%
set HH=%TIME:~0,2%
echo End Hour=%HH%
set MM=%TIME:~3,2%
echo minutes=%MM%
set /a MM=%MM% * 60
echo Total Seconds in given minutes=%MM%
set /a HH=%HH% * 3600
echo Total seconds in given Hours = %HH%
set SS=%TIME:~6,2%
echo seconds= %SS%
Set /a end=%HH% + %MM% + %SS%
echo end time in seconds =%end%
set /a totaltime=%end% - %start%
echo Total Time used in seconds = %totaltime%
C:\>