Julian Date Converter

Convert a calendar date and time (UTC) to Julian Date, Modified Julian Date and day of year.

How to use the Julian Date Converter

Fill in what you know of: Date and time (UTC, empty = now) — leave the unknown empty.
The results (Julian Date, Modified Julian Date, Day of year, UTC) are calculated instantly as you type.
Use “Copy link” to share the calculation with the same input values.

Formula

JD = Unix ms / 86 400 000 + 2 440 587.5
MJD = JD − 2 400 000.5