和暦と西暦の双方向変換をサポートするツール。全元号（新元号・令和））対応。

jcalendaR is a package for converting between current Japanese calendar, old Japanese calendar that Kyureki, and Julian and (proleptic) Gregorian calendar in R.

R package for Handling Japanese Calender

西暦を和暦に変換出力するツール。php5 以上なら動きます

✨A collection of tools to manipulate the Japanese and Western calendars for javascript and typescript.

A thin wrapper for Python's datetime package for simple Japanese calendar dates and time formats.