Calendars

In the last lesson, we talked about two calendars, the Gregorian calendar and the Buddhist calendar (also called the Buddhist era). There are, in fact, several other calendars that are important to familiarize yourself with (get to know) when studying Thai history, as some old documents and sources use dates from these other calendars.

The Julasakarat calendar (จุลศักราช or จ.ศ.) is a luni-solar calendar based on the Burmese calendar. It is important because it was used in Lan Na, the late Sukhothai period, and during part of the Ayutthaya period. Even in the 19^th century, some coins Thai coins are dated using this calendar.

The first year of this calendar starts in 638 AD or 1181 BE. So to make a conversion from the Julasakarat year to the Buddhist year, we add 1181. To make a conversion from the Buddhist year to the Julasakarat year, we subtract 1181.

Another important calendar is the Shalivahana calendar (มหาศักราช or ม.ศ.). This is ancient Indian/Hindu calendar, which was sometimes used in the past in some parts of Thailand.

To make a conversion from the Shalivahana year to the Buddhist year, we add 621. To make a conversion from the Buddhist year to the Shalivahana year, we subtract 621.

As we well know, Thailand has a significant Muslim population. It is therefore, important to understand the Islamic calendar, known as the Hijri calendar (ฮิจเราะห์ศักราช or ฮ.ศ.).

To make a conversion from the Hijri year to the Buddhist year, we add 1122. To make a conversion from the Buddhist year to the Hijri year, we subtract 1122.

The final calendar your need to know is the Ratanakosin era calendar (รัตนโกสินทร์ ศก or ร.ศ.). This calendar is based on the founding of Bangkok, in 2324 BE. It was used in Thailand during the reign of King Rama V (Chulalongkorn). Some old Thai coins are dated using this calendar.

To make a conversion from the Ratanakosin year to the Buddhist year, we add 2324. To make a conversion from the Buddhist year to the Ratanakosin year, we subtract 2324.