Date Time TOOL

Julian Date Converter - JD, MJD, JDN Calculator

Convert Gregorian dates to Julian Date, Modified Julian Date, Julian Day Number, J2000 days, and ordinal day values. Free browser-based JD calculator.

Work with dates and times

Start / input date

End / comparison date

Days / months / years to add

Time (optional)

Result

How to use this tool

Enter or select your input.
Run the tool and review the result.
Copy or download the output when available.

About this tool

Convert Gregorian dates to Julian Date, Modified Julian Date, Julian Day Number, J2000 days, and ordinal day values. Free browser-based JD calculator.

Frequently asked questions

Is my data uploaded?

This tool processes input in your browser. Files and text are not sent to our server by this page.