Day of Year to Date Converter

Free day of year to date converter. Convert ordinal day numbers back to calendar dates. Essential for data processing.

Convert an ordinal day number (1-365/366) back to a calendar date. Enter the day number and year to get the corresponding month and day. Reverses the day-of-year calculation.

Common use cases

  • Interpreting scientific data
  • Programming date conversions
  • Processing date fields in data
  • Converting legacy date formats
  • Educational and research purposes

How to use

  1. Enter the day number (1-365 or 366)
  2. Enter the year
  3. View the calendar date result
  4. Handle leap years correctly
  5. Copy the formatted date

FAQ

What if I enter 366 in a non-leap year?

The tool will indicate the year doesn't have 366 days and show the closest valid date.

Can I enter values over 365?

The tool validates against the year's actual length. Use 366 only for leap years.

How are leap years handled?

Enter the correct year and the tool accounts for February having 28 or 29 days.