Julian Day Converter
Convert a Julian Day Number — the continuous day count used in astronomy — to a calendar date and Unix time.
Reviewed by the CalcCafe editorial team · Last updated 1 July 2026 · How we test our tools
UTC / GMT
Your local time
ISO 8601
Relative
Unix seconds
Unix milliseconds
Current time updating:
How it works
Conversion: JD = unixDays + 2440587.5, where 2440587.5 is the Julian Day of the Unix epoch.
Enter a value to convert it to a human-readable date, or click Use current time. Conversion is two-way and runs entirely in your browser.
Frequently asked questions
What is a Julian Day?
The Julian Day Number is a continuous count of days (and fractions) since noon Universal Time on 1 January 4713 BC. Astronomers use it to avoid calendar complications.
Is it the same as a Julian calendar date?
No — despite the name, the Julian Day Number is just a running day counter, unrelated to the Julian calendar.
People also ask
What are the Julian dates for 2026?
In the astronomical sense, 2026 runs from Julian Day 2461041.5 (2026-01-01 00:00 UTC) to 2461406.5 (2027-01-01 00:00 UTC), since 2026 has 365 days; noon on 1 January 2026 is JD 2461042.0. The arithmetic is 20454 days from the Unix epoch to 2026-01-01, plus the epoch offset 2440587.5. If you mean the ordinal "Julian date" used in manufacturing and logistics, that is just the day of year, 001 for 1 January through 365 for 31 December 2026, often written with the year as 26001 to 26365.
Related tools
Sources & references
These tools follow our methodology and provide educational estimates only — verify important figures with a qualified professional.