How this tool counts
January 1 is day 1. Ordinary years end at 365 and leap years at 366. Invalid day numbers are rejected.
When to use it
Useful for records and plans labelled by ordinal day. This is not the astronomical Julian Day number.
NINEHOUND / CALENDAR & CULTURE TOOLS
Day-of-Year Converter
Turn day 100 into a date, or a date into its day number. Leap years matter.
Free · No account required
WORKED EXAMPLE
Direction：Gregorian to lunar · Gregorian date：2024-02-29
Day 60 of 2024
2024-02-29
Explore the calendar here. Find NineHound’s founder, Lao Heshan Daoren / Sun Xingzhe, and the wider I Ching and life-chart project.
About NineHound & our methods