Perpetual table
Day-of-Year Chart
The classic perpetual Julian date lookup for common (non-leap) years. Every date maps to its day of year, 001–365. For 2024, 2028 and other leap years, use the leap-year chart instead.
| Day | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
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| 31 |
How to use it
Find the day of the month in the left column and read across to the
month; the cell gives the day of the year. Add the year in front to form
a full Julian date code — for example day 202 in 2026 is
2026202 or 26202.
Use the right chart for leap years
This table is for non-leap years. In a leap year every date from 1 March is one day higher. Years divisible by 4 are leap years, except century years not divisible by 400 (so 2000 was, 1900 was not).
Common reference points (non-leap year)
| Date | Day of year |
|---|---|
| Jan 1 | 001 |
| Feb 1 | 032 |
| Mar 1 | 060 |
| Apr 1 | 091 |
| Jul 1 | 182 |
| Oct 1 | 274 |
| Dec 31 | 365 |