Calculating Moon Phases

Please enter a date. Use four digits for years after 999 AD. Use 24-hour time.
Your time zone offset of hours from GMT will be applied to all dates beginning with 1990.

Since there is no year “0” (1 BC immediately preceded 1 AD), for years BC, subtract one year and add a minus sign.
For example, 1 BC = 0, 2 BC = -1, and 343 BC = -342.

Year Mon Day   Hr : Mn

Spinning Moon


If your computer does not display the correct date and time, make sure your system is properly configured.
In Windows, click “Start–Settings–Control Panel–Date/Time” and adjust your date, time, and
time zone to the correct numbers. You may also need to add a line to your autoexec.bat
file that says “SET TZ=EST+05EDT” or whatever is appropriate for your location,
or your browser may think you live in California (Pacific Time).


Copyright © 1996 by J. Stein Carter. All rights reserved.
This page has been accessed Counter times since 22 Jan 2011.

Graph It