Date Converter
Instantly convert dates across 10 major global calendar systems.
Select Date
Calendar Conversions
Disclaimer
This date converter is for general reference and educational use only. Results are based on standard calendar conversion formulas. Some calendar systems use regional or religious variations that may differ from the results shown here. Always verify important dates with a qualified religious or cultural authority.
Expert Review
This content was reviewed by a historian and calendar systems researcher with experience in cross-cultural date research and academic documentation. This tool uses standard conversion methods commonly referenced in astronomy, genealogy, and historical date research. Last updated June 11, 2026.
Sources
- US Naval Observatory — Julian Date and calendar conversion standards
- Library of Congress — Historical calendar documentation and date research
- Smithsonian Institution — World calendar systems and cultural history
- National Institute of Standards and Technology — Time and calendar reference standards
- Encyclopaedia Britannica — Calendar system histories and conversion references
About Date Converter
Date Converter takes any date you enter and shows it across 10 different calendar systems on one screen. Gregorian, Islamic, Hebrew, Chinese, Persian, Julian, and more all come up together. People use it to check religious holidays, historical records, and personal dates without jumping between multiple sites or charts.
Benefits
- Converts one date into 10 different calendar systems in one step.
- Useful for planning around religious observances across Islamic, Hebrew, and Hindu calendars.
- Helps researchers and historians cross-check dates between Julian and Gregorian systems.
- No calendar knowledge needed. Enter a date and all conversions appear together
- Free to use, no account needed, works on any device.
Did You Know?
The Gregorian calendar was not adopted worldwide until centuries after its introduction in 1582. Russia switched from the Julian calendar as late as 1918, which is why some historical Russian events appear to fall on different dates depending on which calendar you check.
How It Works
Pick a date using the date selector on the tool. The converter reads your input and runs it through each calendar system's formula, accounting for each system's unique starting point, cycle length, and leap year rules. All 10 calendar results show up together on one screen. No switching between tabs, no separate tools needed for each system.
When Should You Use This Converter
- Planning events involving guests observing Islamic, Hebrew, or other religious calendars.
- Verifying historical dates recorded before the Gregorian adoption.
- Checking when religious holidays fall on the standard calendar.
- Genealogy research where old records use Julian or Hebrew calendar dates.
Privacy Note
Whatever date you type stays on your screen. Nothing leaves your browser, nothing gets saved. Close the tab, and it is gone.
Formula Used
Every calendar system counts time from a different starting point. This converter turns your date into a Julian Day Number, a neutral reference point that spans all calendar systems. From there, it applies each calendar's own math to produce the final result. This two-step process is the same method used in academic and astronomical date research.
Example
Enter March 15, 2025. The tool converts it to a Julian Day Number behind the scenes, then runs that through each calendar. You get 14 Ramadan 1446 in the Islamic calendar and 15 Adar II 5785 in the Hebrew calendar, along with results for all other systems on the same screen.
How Religious Communities Use a Date Converter
Millions of Americans plan their year around calendars that have nothing to do with January and December. A Muslim family checking when Ramadan starts, a Jewish household confirming Passover dates, a Hindu family planning around Diwali, all of them need to cross-reference their religious calendar against the standard Gregorian one. This tool does that in one step.
Why Genealogy Researchers Rely on Date Conversion
Old family records from Eastern Europe, the Middle East, and Asia were written in Julian, Hebrew, or Persian calendar dates. Anyone tracing their family tree on Ancestry or going through immigration documents from the 1800s regularly runs into this problem. A date converter bridges that gap without needing a history degree to figure it out. Pair it with our Age Calculator to match birth and death records across calendar systems.
How US History Students Use Calendar Conversion
Colonial American records and documents from before 1752 used the Julian calendar, not the Gregorian one that the US follows today. That 11-day difference between the two systems trips up students and researchers working with founding-era documents regularly. Running those dates through a converter keeps the timeline straight without hours of manual cross-referencing.
Pick any date and the converter lines up all 10 calendar systems on one screen in seconds. Whether you are checking a religious holiday, tracing a family record, or researching a historical date, the answer is right there. No sign-up, no cost, works on any device. Looking for other conversions? Try our Conversion Calculator.