Solved MS DOS – How To Get The Day Difference Between

Test this. It is assumed that the second date will always be greater than the first, if not then you should code a routine to check this and branch to a suitable routine.

@echo off
cls
setlocal

set mm=7
set dd=14
set year=2011
call :convjdate
set juldate=%jdate%

set mm=7
set dd=20
set year=2011
call :convjdate
set juldate1=%jdate%

set /a daydiff=%juldate1%-%juldate%

echo Difference=%daydiff% days.
exit /b

:convjdate
:: Convert Gregorian date to Julian date
:: Algorithm based on Fliegel-Van Flandern
:: algorithm from the Astronomical Almanac,
:: provided by Doctor Fenton on the Math Forum
:: (http://mathforum.org/library/drmath/view/51907.html),
:: and converted to batch code by Ron Bakowski.

SET /A Month1 = ( %MM% - 14 ) / 12
SET /A Year1  = %year% + 4800
SET /A jdate  = 1461 * ( %Year1% + %Month1% ) / 4 + 367 * ^
( %MM% - 2 -12 * %Month1% ) / 12 - ( 3 * ( ( %Year1% + %Month1% + 100 ) / ^
100 ) ) / 4 + ^%DD% - 32075

Please come back & tell us if your problem is resolved.