Historical Year Calendar Conversion

Convert reign-year dates to the modern Gregorian calendar.

I. Tool

Operation

Tang · 太宗
貞觀 5年 = 631 CE
Sexagenary year: 辛卯
Era ran 627649 CE (23 years).

Era year 1 is the year the era was proclaimed, so the Gregorian year is start + n − 1. Lunar new year falls in Jan–Feb, so dates in the first weeks of a Gregorian year may belong to the previous era year.

II. Principle

How it works

A bundled table of Chinese dynastic reign eras (年號) with start and end Gregorian years enables lookup in both directions. Extensions cover major Japanese, Korean and Vietnamese eras where reliable open data exists.
III. Guide

User guide

  1. 01Enter a reign name and year number (e.g. 貞觀 5).
  2. 02Or enter a Gregorian year to see which reign eras were in force.
IV. FAQ

Frequently asked

Q.How are era transitions handled?

A.The tool reports both the outgoing and incoming era in transition years.