Click the button to run the Date Calculator applet using Java Web Start.
RUN Date Calculator
Use this Java applet to calculate:
- Days between dates. Enter the first date,
then the second date, then click the = at days
between dates. Example: The number of days between
Thanksgiving (11/27/2003) and Christmas (12/25/2003) this
year is 174 days.
- Date a given number of days forward from another
date. Enter the first date, then the number of
days between dates, then click = for the second
date. Example: If I buy a couch today (10/2/2003) and
have 90 days to pay, then my payment is due on or before
- Date a given number of days backward from another
date. Enter the second date, then the number of
days between dates, then click = for the first
- Day of the week on a given date. Enter the date
in first date (or second date) and press the
enter key. Read the date description in first date
is (or second date is). Example: Abraham Lincoln
gave his Gettysburg Address on 19 Nov 1863, a
- Julian day number for a given date. Enter the
date in first date (or second date) and press
the enter key. Read the date description in first date
is (or second date is).
- Two digit dates. Don't use them. The year "99" is the
same as "0099".
- B.C. dates. In the Julian Calendar, 1 B.C.
immediately preceded 1 A.D. There was no year 0. However,
the applet uses a year 0, which is really 1 B.C. For B.C.
dates, you have to remember that the years are off by
one--10 B.C. to the applet is really 11 B.C. Now,
this won't be much of a loss, because the Julian
calendar only began in 45 B.C. and exact B.C. dates are a
little hard to come by anyway. But suppose you want to
calculate the number of days from the day Julius Caesar was
assassinated (15 Mar 44 B.C.) to the day fire broke out in
the Circus Maximus to destroy Rome (18 July 64 A.D.). Enter
3/15/43 (not 44!) B.C. and 7/18/64 A.D., to learn that
there were 39208 days between those events.
- B.C. leap years. The Romans made a mess of this.
The applet assumes that B.C. leap years are all those
evenly divisible by 4. (Where 1 B.C. is considered to be
- Non-standard countries. The official
Julian-to-Gregorian calendar caused 4 Oct 1582 to be
immediately followed by 15 Oct 1582, but only Italy,
Poland, Portugal, and Spain observed this change. Other
countries now using the Gregorian calendar made the switch
at different times. My state of Illinois was at the time a
colony of France, and made the switch later--9 Dec 1582 was
followed by 20 Dec 1582. To account for non-standard
calendar changes, click the Options button and enter the
last date of the Julian calendar and the first date of the
Gregorian calendar for the particular country of
interest. Claus Tøndering (http://www.tondering.dk/claus/calendar.html)
has compiled a list of various country-specific calendar
- Today's date. When the applet is first
initialized it reads the current date from the server. Of
course, this is the current date where the server is, not
necessarily where you are. If it is incorrect, click the
Reset button to use your own computer's date.
- Limitations. Only dates from 1 Jan 4713 B.C. to
1 Jan 3266 A.D. are allowed. Dates prior to 45 B.C. are in
the "Julian Proleptic Calendar", convenient for modern
dating, but not used by any ancient peoples.
Last revised 15 Oct 2016