What does this tool do
The Calendar Converter converts between six calendar systems: Gregorian (solar, international), Vietnamese Lunar (âm lịch), Chinese Lunar (农历), Islamic (Hijri) (Umm al-Qura), Hebrew (Jewish), and Persian (Jalali). Choose a "From" and "To" calendar, enter a date in the source calendar, and see the equivalent date in the target calendar. All conversions use Gregorian as the pivot. Useful for traditional holidays (Tết, Lunar New Year, Ramadan, Jewish holidays, Nowruz), anniversaries, and cultural events.
How to use it
- Choose calendars — Select "From calendar" (e.g. Gregorian) and "To calendar" (e.g. Vietnamese Lunar, Chinese Lunar, Hijri, Hebrew, or Jalali).
- Enter date — Enter day, month, and year in the source calendar. For Vietnamese Lunar or Chinese Lunar, tick "Leap month" if the date falls in an intercalary month.
- View result — The converted date appears below. For Vietnamese Lunar, localized month names are shown; for Chinese Lunar, the result includes the original Chinese text (e.g. 十五, 正, 二〇二六). For Hebrew, the month name (e.g. Cheshvan) may be shown.
- Copy — Use the copy button to copy the result.
How it works
The tool uses Gregorian as the pivot: From calendar → Gregorian → To calendar. Libraries used:
- Vietnamese Lunar:
lunar-javascript— lunisolar algorithm with leap months; UI shows localized month names (e.g. Giêng, Hai). - Chinese Lunar: same underlying lunisolar system as Vietnamese Lunar via
lunar-javascript; result shows original Chinese text (e.g. 正月, 十五, 二〇二六). Vietnamese and Chinese lunar calendars share the same system; official Vietnamese dates may rarely differ by one day due to timezone or regional rules. - Hijri:
hijri-converter— Umm al-Qura calendar; supported range is approximately 1343–1500 AH (1924–2077 CE). Accuracy is not independently verified. - Hebrew:
@hebcal/core(HDate) — Jewish lunisolar calendar; supports full year range used by the library. - Jalali:
jalaali-js— Persian solar calendar (Borkowski algorithm); typically accurate for 1800–2256 CE.
All computation runs in your browser. No data is sent to any server.
Use cases & examples
- Tết — Find the Gregorian date of Vietnamese New Year (lunar 1/1).
- Ramadan / Eid — Convert between Hijri and Gregorian for Islamic holidays.
- Jewish holidays — Convert Hebrew dates to Gregorian (or the other way).
- Nowruz — Jalali 1/1 is the Persian New Year (around 20–21 March Gregorian).
- Annals — Convert birthdates or historical events across calendars.
- Dual calendar — Keep track of the same day in multiple systems.
Examples
- Gregorian 20 March 2024 → Jalali 1/1/1403 (Nowruz).
- Hijri 1 Ramadan 1446 → Gregorian equivalent (date depends on year).
- Hebrew 15 Cheshvan 5784 → Gregorian equivalent.
Limitations & known constraints
- Vietnamese lunar — Listed separately from Chinese Lunar for clarity; same lunisolar system. Naming follows Vietnamese usage; leap months must be indicated when converting lunar → Gregorian.
- Chinese lunar — Listed separately for SEO and display; same lunisolar system as Vietnamese. Result shows original Chinese characters (农历). Official Vietnamese and Chinese dates may rarely differ by one day.
- Hijri — Umm al-Qura; supported range is limited (see library docs). Other Hijri variants (e.g. calculated) may differ.
- Hebrew — Uses the algorithms in @hebcal/core; not independently verified.
- Jalali — Solar calendar; algorithm may diverge from Intl/other implementations outside the typical supported range.
- Library dependency — Accuracy depends on the respective libraries; not independently verified by this project.
- Range — Each library may have a supported year range; outside range may throw or return incorrect results.