What is the Julian Date Converter?
The julian date converter is a free online tool that helps you work out julian date quickly and accurately. It uses the standard formula Convert a Gregorian date to its Julian day number and day-of-year and shows the result instantly as you type, along with a full breakdown so you can see exactly how the answer was reached.
How to use this calculator
- Enter a calendar date.
- See the Julian day number.
Formula used
Convert a Gregorian date to its Julian day number and day-of-yearExplanation of each input
- Calendar date โ the calendar date used in the calculation.
Understanding your result
- Julian day number โ the calculated julian day number.
- Day of year โ the calculated day of year.
Step-by-step calculation
For the example values 2000-01-01:
- Apply the formula:
Convert a Gregorian date to its Julian day number and day-of-year - Substitute the values: algorithm
- Result: JDN 2451545
Worked example
| Inputs | 2000-01-01 |
|---|---|
| Working | algorithm |
| Result | JDN 2451545 |
Benefits and practical uses
This calculator saves you time and reduces errors when you need julian date. It is useful for students, professionals and anyone who wants a fast, reliable answer without manual calculation. Results update instantly, work in your browser and can be copied or shared in one click.
Assumptions and limitations
- Gregorian calendar input.
Frequently asked questions
What is a Julian day?
A continuous count of days used in astronomy, starting from 1 January 4713 BC.
Disclaimer: Results are provided for general information. Please verify important figures independently.