Wesak full-moon is the auspicious ‘Buddha Day’. According to Theravada tradition, this day commemorates three important events in the Life of our Great Teacher – His birth in the year 623 BCE; His Enlightenment in 588 BCE; and His Parinibbāna in 543 BCE. The ‘Buddha Day’ on 26 May 2021 marks the beginning of Year 2565 of the Buddhist Era (B.E.), or more commonly expressed as B.E.2565. In Pāli language, the Buddhist Year is termed ‘Buddhavasse’.
But how exactly do you derive the Buddhist Year 2565?
Why do we add 544 to the present year? Unlike the Christian Era, which began with the birth of Jesus Christ, the Buddhist Era began with the Parinibbāna or Passing away of the Buddha in the year 543 BCE (BCE: Before Common Era). Thus 543 BCE, the year when the Buddha passed away, is Year 1 of the Buddhist Era (or B.E. 1). To derive 544, we add 543 years + 1 year, which is the year 0 CE.
Hence, the Buddhist Year for 2021 is B = 544 + 2021 = B.E. 2565.
By convention, the Buddhist Year starts with Wesak full-moon in the month of May. Therefore, before ‘Buddha Day’ on 26 May 2021, the year is B.E.2564. On ‘Buddha Day’, a new Buddhist calendar year begins – Buddhist Era 2565.
However, in Thailand, the Buddhist Year is taken to start on 1 January instead of in April / May, so as to synchronize with the Common Era calendar. Furthermore, the Buddhist Year is one year behind the calculation presented here, i.e. Year 2565 recognised in Sri Lanka, Malaysia and Singapore is equivalent to Year 2564 in Thailand. The reckoning of the Buddhist Era (“Buddha Sakarat”) in Thailand is 543 years ahead of the Common Era, thus the year 2021 CE corresponds to B.E. 2564.