The positivist calendar was a proposal for calendar reform proposed by Auguste Comte in 1849. After revising the earlier work of Marco Mastrofini , Comtes proposed calendar was a lunisolar calendar which had 13 months of 28 days, and a additional festival day commemorating the dead. This extra day added to the last month is outside of the days of the week cycle, and so the first of a month is always a Monday. On leap years an additional leapday to celebrate holy women would join the memorial day of the dead. The scheme followed the Gregorian Calendar's rules for determining which years are leap years, and started on January 1. Year 1 "of the Great Crisis" according to this calendar would be equivalent to the year 1789 in the Gregorian system. Much like Comte's other schemas, the positivist calendar never enjoyed widespread use.

Months were named for:

1. Moses
2. Homer
3. Aristotle
4. Archimedes
5. Caesar
6. Saint Paul
7. Charlemagne
8. Dante
9. Gutenberg
10. Shakespeare
11. Descartes
12. Frederic
13. Bichat