Calendar Wiki

The 10–10 calendars have 9 equal length divisions of the year (each divisible by 10) and one extra division with the remaining days, the last 5 (common year) or 6 (leap year) not falling on any day of the decaday.

10–10 calendar for Earth[]

Epoch
22 September 1792 AD
Year 0
No
Leap day
Every year divisible by 4 but not 128 using von Mädler (calculated method), or observed (matching the French Republican Calendar)
Subdivisions of the year
deciyear (40 days for the first 9 and 5 or 6 days for the last)
decaday (10 days, none in the last deciyear)
day
deciday (0.1 days, 2.4 hours or 144 minutes)
milliday (0.001 days, 1.44 minutes or 86.4 seconds)
centi-milliday (0.00001 days, 0.864 seconds)