Dusk has 27 hours per day, and 243 days per year (both decimal, it's 30 and 300 days respectively in nonary).
This tool is meant to provide a rough approximation — proportionally — of when something might have occurred within the year for one system or the other.
For more information, see Time and Timekeeping.
Warning: Don't use a date ending in 9 for your day. This doesn't exist in the Dusk. You'll get an error.
Leap years don't exist here.
This thing will do weird things if your date is invalid.