Alternative and Proposed Calendars

Below is a list of calendars that either

have been proposed as candidates for a new calendar to replace the commonly used one,
have been devised for some particular purpose (e.g., staying in sync with the Moon's phases, or for living on Mars),
have been invented because the calendar maker felt the urge to do so or
for some or all of these reasons.

This list also includes calendars of dubious historicity and some that are perhaps not entirely serious.

Proposed calendars

Also see: Proposed calendars

Reformed calendars

The Prospects for Gregorian Calendar Reform

12&12

13+13

30,30,31 Ossipoff Minimum-Displacement

30x11 Calendar

360 Dates Calendar

4 weeks a month calendar

52-Week Calendar

6-Day Week Solar Calendar with common Muslim/Christian weekend

8-days a week simple calendar

A1 Calendar

Alternate month Gregorian calendars

Alternate month names for use with leap week calendars

Alternate month names for use with Symmetry Calendars

Alternative month names for use with Accounting Leap Week Calendars

Amended Julian Worldwide Calendar

Common-Civil-Calendar-and-Time

User blog:Crissov/Extensions to ISO 8601 date and time formats

Day of Quarter notation for Gregorian Calendar

Deciyear Calendar

Dee calendar

Dee-Cecil calendar

Dominical Letter Calendar

Earth Calendar

Earth Epic Calendar

Edwards perpetual calendar

Fixed Quarters Calendar

Gorman Calendar

Hanke-Henry Permanent Calendar

Hermetic Leap Week Calendar

Holocene calendar

International Easter Calendar

International Fixed Calendar

Invariable Calendar

ISO-Uncia Leap Week Calendar

Jaktober

Long Summer Modified Gregorian Calendar

Long-Sabbath Perennial Calendar

Luni-solar Modified Gregorian Calendar

Minimum Displacement Calendar

Modified Gregorian Calendar

Month naming

Nepturan Calendar Rule

New Earth Calendar

New Reform Calendar

North American Weekday Holiday Act

Octalendar

Olympiad Calendar with Smoothly Spread Month Lengths

Pataphysical Calendar

Pax Calendar

Perennial Dominical Letter Calendar

Permanent International Calendar

Pregordian Calendar

Quepennura Calendar

Revised Julian calendar

Sol Calendar

Sonny Pondrom calendars

Truncated Dee-Cecil Calendar

Week & Month Calendar

Weekdate

Whole Weeks Calendar

World Calendar

World Calendar with Leap Weeks

Alternative calendars

Calendars by days per week
3–6 days per week	7 days per week	8–10 days per week
A Calendar for Time to Come Liberalia Triday Calendar Shift Calendar Trical Igbo calendar Yoruba calendar Annus Novus Decimal Calendar Christian Calendar Decimal calendar Long Summer Modified Gregorian Calendar Luni-solar Modified Gregorian Calendar Messiah’s Calendar Newcal Quinta Calendar Shift Calendar Soviet revolutionary calendar Traditional Christian Calendar Tyerian Calendar 28-hour day 54-Week Calendar 6-Day Week Solar Calendar with common Muslim/Christian weekend 60-Week Calendar Akan calendar Albertan calendar Blanxart Calendar Double Rainbow Calendar Fixed Week Calendar Global Decimal Calendar Heximal Calendar Primavera Calendar Sexagesimal calendar Shift Calendar Soviet revolutionary calendar Triangular Earth Calendar	42-49-day month calendars 56-63-day month calendars Week starts Friday Week starts Monday Week starts Saturday Week starts Sunday Week starts Thursday Week starts Tuesday Week starts Wednesday 28-hour day 30x11 Calendar 4 weeks a month calendar 54-Week Calendar Akan calendar Balanced French Calendar Cal7 Christian Calendar Day of Quarter notation for Gregorian Calendar Easter Calendar Enoch Calendar Fixed Festivity Calendar Fixed Festivity Week Calendar Fixed Quarters Calendar Hindu calendar Petin-Meton calendar Playing Card Calendar Qumran Calendar Riparian Calendar Runic calendar Symmetry454 Calendar Thursday rule Traditional Christian Calendar Week & Month Calendar Weekend Rest Calendar Yoruba calendar	352 Or 384 Day Calendar 8-days a week simple calendar Fixed Festivity Calendar Fixed Festivity Day Calendar Modern Calendar New Roman Lunisolar Calendar Petin-Meton calendar A Calendar for Time to Come Deciyear Calendar Kalentris Shift Calendar Trical 10–10 calendars 6610 regular calendar Archetypes Calendar Balanced French Calendar Decimal 3-Year Calendar Decimal calendar Egyptian calendar Freeman Calendar French Republican calendar Shift Calendar Tenstrong Calendar UCC 'Peacock's Tail' Calendar Universal Celestial Calendar