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.
- Also see: Proposed calendars
|3–6 days per week||7 days per week||8–10 days per week|
Calendars with 7 day week plus some extrahebdomadal days (days outside of 7-day week)
Thiruvalluvar Calendar (extra one day in Normal year and two days in leap year are added at the end of 4th week (Last week of first month). These days are assigned to rare weekdays like Thasathi and Netti.
Super Calendar (normal weeks and one super week(9 days))
Permanent International Calendar (Special week added in end of second month)