< Conversion Calculators

Convert Day Number to Date

Convert day number to corresponding calendar date, showing any date difference if year is leap year or non-leap year.

Entry Fields

Specify the day number you want to convert to a date. Valid range is from day number 1 of the year to day number 366. Note that day number 366 will only be valid in leap years. For non-leap years, up to day number 365 is valid.

Optionally, if you enter a year, the day number you specify is converted to the month and day in that year. If you leave year blank, the current year is used.

FYI - Day number will always convert to the same date (month and day of month) for the first 59 days of any year, regardless of whether or not it's a leap year. However, from day number 60 onward, the date on which a day number occurs differs by one day, depending if the year is a leap year or a non-leap year.

To show this, when day number is between 60 and 365, inclusive, the conversion will include the corresponding date for both the year specified (or current year), as well as the next leap or non-leap year. That is, if day number is converted for a leap year, the conversion will also include the next non-leap year; If day number is for a non-leap year, the conversion will include the next leap year.