Revolutionary calendar tool
Convert Gregorian dates into the calendar of the First Republic, switch back from Republican dates, and watch the day pass in decimal time.
Dates before 22 September 1792 have no Republican equivalent.
Messidor 2, Year 234 (decade 1)
Messidor · Decade 1 · Day 272
The French Republican calendar was introduced during the Revolution to replace royal, Christian, and Roman traces in everyday timekeeping with a rational civil system. Year 1 began on 22 September 1792, the day after the monarchy was abolished and close to the autumn equinox in Paris. The year was divided into twelve poetic months of thirty days, from Vendemiaire and Brumaire through Thermidor and Fructidor. Each month had three ten-day decades instead of seven-day weeks.
At the end of the twelve months came the sansculottides, five complementary festival days, or six in a leap year. This converter uses the proposed Romme rule: leap years are divisible by four except century years, unless divisible by 400. That makes the arithmetic clear and repeatable, though historical almanacs tied some early years to the observed Paris equinox.
Revolutionary reformers also tried decimal time: ten hours in a day, one hundred minutes in an hour, and one hundred seconds in a minute. It was elegant on paper but awkward for clocks, churches, markets, and habits. Napoleon abolished the Republican calendar from 1 January 1806, restoring Gregorian civil dates. The Paris Commune briefly revived Revolutionary dating in 1871, more as political symbolism than as a durable replacement for ordinary time.