World Calendars Converter
Convert any date across six world calendar systems at once: Gregorian, Hijri, Hebrew, Persian, Japanese Era, and Buddhist.
1 January 2026 CE
2026-01-01
Thursday
Conversion
| Calendar | Conversion |
|---|---|
| Hijri (Islamic) | 12 Rajab 1447 AH |
| Hebrew (Jewish) | 12 Tevet 5786 AM |
| Persian (Solar Hijri) | 11 Dey 1404 SH |
| Japanese Era | Reiwa (令和) 8, January 1 |
| Buddhist | 1 January 2569 BE |
| Chinese Lunar | 13 day of the 11th lunar month, 乙巳 (2025) |
| Vietnamese Lunar | 13 day of the 11th lunar month, 乙巳 (2025) |
| Korean Lunar | 13 day of the 11th lunar month, 乙巳 (2025) |
| Julian | 19 December 2025 CE |
World calendars converter. Convert any date across 6 calendar systems at once.
A world calendars converter shows the same date written in multiple cultural calendar systems simultaneously: Gregorian, Hijri (Islamic), Hebrew (Jewish), Persian (Solar Hijri), Japanese Era, and Buddhist. Pick any calendar as your input and instantly see the equivalent in every other system, plus day of week and ISO-8601 format.
What Is the World Calendars Converter?
Six major calendar systems are in use around the world today, and a date in one tells you nothing about the date in another. Most calendar converters online support only one or two systems at a time; this one shows all of them in parallel.
Each calendar has its own epoch, leap year rules, and month structure. The Gregorian calendar (used internationally) counts years from a date close to the birth of Jesus. The Hijri calendar counts from the Prophet Muhammad's migration to Medina in 622 CE. The Hebrew calendar counts from the traditional creation date in 3761 BCE. The Persian calendar shares the Hijra event but tracks solar years. The Japanese Era calendar resets with each emperor's reign. The Buddhist Era used in Thailand counts from the Buddha's parinirvana, 543 years before the Common Era.
This converter unifies them all behind a single Julian Day Number pivot, so any date in any calendar can be translated to any other with a single click.
How Calendar Conversion Works
Every calendar conversion in this tool goes through the Julian Day Number (JD) — an integer count of days since 1 January 4713 BCE proleptic Julian. Each calendar has algorithms to convert a date to a JD and back from a JD to a date.
1. Pick your origin calendar from the dropdown.
2. Enter the date in that calendar's day, month, and year.
3. The tool computes the JD and converts to every other calendar.
4. Each output card shows the date in that calendar plus contextual extras (era label, upcoming festivals, special-period markers).
The conversion is exact for arithmetic calendars (Gregorian, Hijri tabular, Hebrew, Persian Birashk, Japanese Era, Buddhist) and accurate to the day for all dates within the supported input range of each calendar.
The Julian Day Pivot
- = Julian Day Number — universal day counter shared by all calendar systems
- = Forward conversion from origin calendar to JD
- = Inverse conversion from JD to target calendar
Every calendar converter chains a forward and an inverse conversion through Julian Day. This guarantees consistency: converting Gregorian → Hijri → Hebrew → Gregorian round-trips to the same input date.
Day-of-week and ISO-8601 are derivable directly from the JD, independently of which calendar is in use.
Conversion Examples
1 May 2026 in every calendar
1 May 2026 (Gregorian) = 14 Dhu al-Qa'dah 1447 (Hijri) = 14 Iyar 5786 (Hebrew) = 11 Ordibehesht 1405 (Persian) = 1 May Reiwa 8 (Japanese) = 1 May 2569 (Buddhist).
Hijri New Year 2026
1 Muharram 1448 (Hijri) ≈ 17 June 2026 (Gregorian). The Hijri year is ~354 days, so the new year drifts 11 days earlier each Gregorian year.
Reiwa to Gregorian
Reiwa 7 = 2025 (Gregorian). The Reiwa era began on 1 May 2019 with Emperor Naruhito's accession. Year 1 of any Japanese era is called 元年 (gannen).
Tips for Using This Calendar Converter
- Day and month inputs are still meaningful even for year-shift calendars like Buddhist or Japanese Era — they just pass through unchanged in the conversion.
- Hijri month and day are recomputed via the lunar calendar, so the date number changes (not just the year).
- Hebrew leap years insert Adar I before Adar II — the input dropdown automatically shows 13 months when the year is leap.
- Persian month and day differ from Gregorian because the Solar Hijri calendar starts at the spring equinox.
- Use the share button to copy a URL that preserves your conversion query.
Calendar Conversion Frequently Asked Questions
How accurate is the Hijri conversion?
This tool uses the tabular Islamic calendar (Kuwaiti algorithm). It is accurate to within ±1-2 days of the Umm al-Qura observation-based calendar used in Saudi Arabia. For local moonsighting variations, consult your community's official calendar.
Why does the Hebrew year sometimes have 13 months?
The Hebrew calendar is lunisolar with a 19-year Metonic cycle. Years 3, 6, 8, 11, 14, 17, and 19 of each cycle are leap years and contain an extra month (Adar I) inserted before Adar II to keep the calendar aligned with the solar year.
What is the difference between Hijri and Persian Solar Hijri?
Both calendars start counting from the Hijra event in 622 CE. The Hijri calendar is purely lunar (~354 days/year), so it drifts ~11 days earlier each Gregorian year. The Persian Solar Hijri is solar (~365.25 days/year) and stays aligned with seasons.
Can I convert dates before the year 1 in each calendar?
Each calendar has its own valid range. The Gregorian is proleptic (works for any year, with negative years for BCE). Hijri starts year 1 (= 622 CE). Hebrew supports very early years through a continuous calculation. Persian and Japanese Era have practical lower bounds the tool will warn you about.
Why does my Buddhist date show pre-1941 warnings?
Thailand's official new year was April 1 before 1941. For dates in January–March of years 2432–2483 BE, the offset to Gregorian is 542, not 543. The tool applies this rule automatically and shows an info note.
Is this tool free?
Yes. All conversions run in your browser, no signup, no payment, no data sent to a server.
Glossary
Julian Day Number (JD)
Continuous count of days since 1 January 4713 BCE Julian proleptic. Used as the universal pivot for calendar conversion.
Anno Hegirae (AH)
Era marker for the Hijri calendar; counts years from the Prophet Muhammad's migration to Medina in 622 CE.
Anno Mundi (AM)
Era marker for the Hebrew calendar; counts years from the traditional date of creation, 3761 BCE.
Buddhist Era (BE)
Era used in Thailand and other Theravada countries; offset +543 from Common Era.
Solar Hijri
The Persian solar calendar, sharing the Hijra epoch but using astronomically-determined solar years.
Lunisolar calendar
A calendar that tracks both lunar months and solar years, inserting leap months to stay aligned. Hebrew and Chinese are lunisolar.
Era (元号)
In the Japanese calendar, the named period of an emperor's reign. The current era is Reiwa, started 1 May 2019.
Sources & References
- Julian day — the continuous day count every conversion on this page pivots through. Nothing here converts one calendar straight into another: each system maps to a Julian day number and back, which is why a Hebrew-to-Hijri conversion cannot accumulate a rounding error the two-step route would introduce.
- Unicode LDML Part 4: Dates — the specification covering the calendar identifiers used here (gregory, buddhist, islamic, hebrew, persian, japanese, chinese, dangi) and the month-naming conventions each one requires.
- K. M. Borkowski, "The Persian calendar for 3000 years", Earth, Moon and Planets 74 (1996) 223–230 — the breaks-table algorithm behind the Solar Hijri conversion here. The Persian calendar is observational: its year opens on the day after the March equinox at the 52.5°E meridian, on a 33-year cycle no closed formula reproduces. Borkowski's table is what tracks it; Birashk's 2820-year arithmetic cycle is a different calendar and puts Nowruz 1404 a day early.
- Dershowitz and Reingold, Calendrical Calculations — the standard reference behind the Hebrew arithmetic implemented here, including the Metonic cycle and the four postponement rules for Rosh Hashanah.
- Hong Kong Observatory — Gregorian-Lunar Calendar Conversion Table, the published tables the East Asian lunisolar data is checked against. Those calendars are observational, so this tool ships a precomputed table for 1891–2100 rather than a formula.
- Tabular Islamic calendar — the Kuwaiti arithmetic variant used for the Hijri column, and the reason a calculated Hijri date can differ by a day or two from Umm al-Qura or from a locally sighted crescent.