Datetime Tools
Global calendar converter.
Start with one Gregorian date and see how five established calendar systems write it, including their localized month and era names.
Gregorian date
Localized results
Choose a Gregorian date to see the localized formats.
What this converter includes
The conversion and localized names come from the browser's standards-backed Intl.DateTimeFormat calendar data. Results are formatted in UTC after the Gregorian date is validated, which keeps date-only input deterministic.
| Calendar | Native label | Input range disclosure |
|---|---|---|
| Japanese Wareki | 和暦・元号 | Meiji 1 (modern boundary 1868-10-23) onward |
| Thai Buddhist | ปฏิทินพุทธศักราช | Gregorian input 0001-01-01 through 9999-12-31 |
| Taiwan ROC / Minguo | 民國紀年 | Minguo 1 (1912-01-01) onward |
| Ethiopian | የኢትዮጵያ ዘመን አቆጣጠር | Gregorian input 0001-01-01 through 9999-12-31 |
| Persian Jalali | گاهشماری جلالی | Gregorian input 0001-01-01 through 9999-12-31 |
Why Nepali BS is not included
Nepali Bikram Sambat is intentionally excluded. The current standards runtime resolves ne-NP-u-ca-nepali to Gregorian rather than a Nepali calendar, and this shelf has no independently reviewed local algorithm or authoritative test-vector set for the historical table. Showing a guessed table would look precise while being unsafe around month boundaries, so this tool does not do that.
Sources and method
- ECMAScript Internationalization API defines the calendar identifiers exposed by
Intl.DateTimeFormat. - Unicode LDML / UTS #35, Dates defines calendar data, era boundaries, localized names, and calendar preferences.
- Unicode CLDR charts publish the locale data used for the localized labels.
Browser support: available calendars are feature-detected. If a browser's ICU data does not expose one of the five calendars, the result is marked unavailable instead of silently falling back to Gregorian.