Julian Day Converter
Convert between Julian Day Number (JDN) and Gregorian calendar date. Also calculates Modified Julian Date (MJD). Used in astronomy and chronology.
JD starts at noon UTC. JDN is the integer part.
How to Use the Julian Day Converter
- Enter the required date, time, or duration values.
- Select any additional options such as time zone or format.
- View the computed result instantly.
- Copy the result or adjust inputs as needed.
Référence rapide
| De | Vers |
|---|---|
| 1 minute | 60 seconds |
| 1 hour | 3,600 seconds |
| 1 day | 86,400 seconds |
| 1 week | 604,800 seconds |
| 1 year | 31,536,000 seconds |
| 1 year | 525,600 minutes |
Cas d'utilisation
- •Tracking elapsed time for productivity or time management.
- •Setting precise intervals for cooking, exercise, or training.
- •Planning schedules and events across different time zones.
- •Calculating durations and deadlines for project management.
Questions fréquemment posées
What is Julian Day Number?
Julian Day Number (JDN) is a continuous count of days since the start of the Julian Period (January 1, 4713 BC). It is widely used in astronomy to calculate time intervals.
What is Julian Date vs Julian Day Number?
Julian Day Number (JDN) is an integer, while Julian Date (JD) includes a fractional part for the time of day. JD begins at noon UTC, so JD 0.5 = midnight.
What is Modified Julian Date?
Modified Julian Date (MJD) = JD − 2,400,000.5. It starts at midnight on November 17, 1858 and uses smaller numbers for modern dates.
Why does astronomy use Julian days?
Julian Day Numbers provide a simple way to calculate the number of days between any two dates without worrying about months, leap years, or calendar reforms.
What date is JD 0?
JD 0 corresponds to noon on January 1, 4713 BC in the proleptic Julian calendar (November 24, 4714 BC in the proleptic Gregorian calendar).