Difference Between Dates and Optional Times
Start Date:   ±Y  M  D Start Time:   H M S
Calendar Mode:   Julian            Gregorian
End Date:   ±Y  M  D End Time:   H M S 
Calendar Mode = Gregorian


Start Date/Time   = 2018 April 21 Sat 12:00:00.000
Julian Date       = 2458230
Julian Day Number = 2458230

————————————————————
2018           April

Su Mo Tu We Th Fr Sa
 1  2  3  4  5  6  7 
 8  9 10 11 12 13 14 
15 16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30
————————————————————


*******************************************************


End Date/Time     = 2018 April 21 Sat 12:00:00.000
Julian Date       = 2458230
Julian Day Number = 2458230

————————————————————
2018           April

Su Mo Tu We Th Fr Sa
 1  2  3  4  5  6  7 
 8  9 10 11 12 13 14 
15 16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30
————————————————————

DIFFERENCE BETWEEN DATES AND TIMES
= (JD2 − JD1) = 0 d
= 0 Gregorian yr
=  0d  00h 00m 00s