Date Guides
How countries count years: Japanese era names, the Thai Buddhist Era, lunar calendars and the rules behind the date tools, with the official sources for each.
Japanese Era Names and Western Years
The first day of each era from Meiji to Reiwa, why 1989 has two names, 元年 and dates before 1873.
Read guide →The Thai Buddhist Era and Western Years
B.E. = A.D. + 543, the old 1 April new year, the nine-month year 2483 and old documents.
Read guide →Korean, Chinese and Vietnamese Lunar Calendars
Why Seollal, the Chinese New Year and Tết can fall on different days, leap months and lunar birthdays.
Read guide →Use the Date Tools
The guides explain the rules; the tools convert dates in your browser.
Frequently Asked Questions
Which sources do the date tools follow?
Each guide and tool page lists the official sources it relies on, such as Japanese laws and imperial edicts or the National Library of Thailand, with the date they were last checked.
Are the dates I enter stored?
No. The date tools run in your browser, and what you enter is not sent to LeedyBox or saved.