13Cal
@13cal.net
See the 13 month calendar: 13 equal months of 28 days, every date on the same weekday forever. Free interactive tool, date converter, and printable 2026 & 2027 calendars.
13Cal's Company Logos
13Cal's Brand Colors
Hex Code
Color name
RGB
HSL
CMYK
#14B8A6
Mountain Meadow
20, 184, 166
173, 80, 40
89, 0, 10, 28
#1E293B
Mirage
30, 41, 59
217, 33, 17
49, 31, 0, 77
#FECACA
Your Pink
254, 202, 202
0, 96, 89
0, 20, 20, 0
About 13Cal
13cal.net is an informational website and interactive tool focused on the 13-month calendar, also known as the International Fixed Calendar. This perpetual solar calendar organizes the year into 13 equal months of 28 days, with an additional Year Day and, in leap years, a Leap Day. Its structure keeps dates on the same weekday each year, making months and quarters uniform.
Visitors can explore an interactive calendar, convert Gregorian dates, find their fixed-calendar birthday, and track moon phases. The site explains how the system works, including the added month Sol, positioned between June and July, and compares the fixed calendar with the Gregorian calendar. It also offers guides on the calendar’s history, design, and potential uses in planning and reporting.
For users who want a printed version, 13cal.net sells a $7 digital calendar covering 2026 and 2027. The download includes 26 dated month spreads with marked moon phases, in three printable editions formatted for US Letter and A4 paper.
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