Numistify guide
How to Read the Date on a Thai Coin
Thai coins use their own digits and their own calendars. Neither is hard once you know them: ten symbols and three simple sums turn any Thai date into a Western year.
The short answer
Thai coins are dated in Thai numerals, usually in the Buddhist Era: subtract 543 to get the Western year, so BE 2500 is 1957. Older coins may use the Rattanakosin Era (add 1781) or the Chula Sakarat (add 638), and the Thai digits ๐ to ๙ are read left to right like Western ones.
The four steps
Reading a Thai date comes down to four steps, and the rest of this guide walks through each one:
1. Find the date. Look for a short group of Thai digits. On many coins it is introduced by a two-letter abbreviation with dots, such as พ.ศ., which tells you the era.
2. Read the digits. Turn each Thai digit into its Western equivalent using the table below.
3. Identify the era. Use the abbreviation if there is one; if not, the size of the number tells you.
4. Convert. One subtraction or addition gives the Western year.
Thai numerals and their Western equivalents
Thai has its own ten digits. They work exactly like Western digits — the same place values, read left to right — only the shapes differ.
| Thai | Western | Thai | Western |
|---|---|---|---|
| ๐ | 0 | ๕ | 5 |
| ๑ | 1 | ๖ | 6 |
| ๒ | 2 | ๗ | 7 |
| ๓ | 3 | ๘ | 8 |
| ๔ | 4 | ๙ | 9 |
Some digits look alike, and wear makes it worse. If a digit is unclear, compare it carefully with the table, and check whether the converted year falls inside the years the coin was actually struck.
The three eras on Thai coins
Thai coins are dated in one of three counting systems. Each has a Thai abbreviation, and each one tells you which sum to use.
| Era | Abbreviation | Used officially | To get the Western year |
|---|---|---|---|
| Buddhist Era (BE) | พ.ศ. | From 1912, today | subtract 543 |
| Rattanakosin Era (RS) | ร.ศ. | 1889 to 1912 | add 1781 |
| Chula Sakarat (CS) | จ.ศ. | Until 1889 | add 638 |
No abbreviation? The size of the number gives the era away, because the three ranges never overlap: a four-digit year starting 24 or 25 (2400s, 2500s) is Buddhist Era; a three-digit year in the 100s is Rattanakosin; a four-digit year in the 1100s or 1200s is Chula Sakarat.
Converting to a Western year
Buddhist Era: subtract 543. BE 2500 is 2500 − 543 = 1957.
Rattanakosin Era: add 1781. Year 1 of this era is the founding of Bangkok in 1782, so RS 127 is 127 + 1781 = 1908.
Chula Sakarat: add 638. CS 1236 is 1236 + 638 = 1874.
Worked examples
พ.ศ. ๒๕๐๐ — the abbreviation says Buddhist Era. The digits read 2-5-0-0, so 2500. Subtract 543: 1957.
ร.ศ. ๑๒๗ — Rattanakosin Era. The digits read 1-2-7, so 127. Add 1781: 1908, the year the satang coinage began.
๒๕๑๗ with no abbreviation — a four-digit number starting 25, so Buddhist Era. 2517 − 543 = 1974.
จ.ศ. ๑๒๓๖ — Chula Sakarat. 1236 + 638 = 1874.
The April catch, for dates before 1941
Until 1941 the Thai year did not begin on 1 January. From 1889 it began on 1 April, so each Thai year ran from April to the following March and straddled two Western years.
The sums above give the Western year in which most of the Thai year fell — April to December. A coin struck in January, February or March of that Thai year was actually struck in the next Western year. Since the date on a coin shows only the year, a pre-1941 date really means “this year, or possibly early the next”.
On 1 January 1941 Thailand moved its New Year to January. The year BE 2483 was cut to nine months, April to December 1940, and from BE 2484 (1941) onward the Buddhist Era lines up exactly with the Western year: subtract 543 and you are done.
A short history of the Thai calendar
Chula Sakarat. For centuries Siam counted years in the Chula Sakarat, an era shared with Burma whose year zero falls in 638. It remained the official reckoning until 1889, and it is the era on the older coins.
The Rattanakosin Era, 1889. King Chulalongkorn (Rama V) replaced it on 1 April 1889 with the Rattanakosin Era, counting from the founding of Bangkok as the capital in 1782, and moved official life onto a solar calendar starting each year on 1 April. Coins struck from 1889 to 1912 carry RS dates; his earlier coins still carry Chula Sakarat dates.
The Buddhist Era, 1912. In 1912 (BE 2455) King Vajiravudh (Rama VI) switched the year count to the Buddhist Era, which runs 543 years ahead of the Western count. Rattanakosin dating ended at RS 131.
January New Year, 1941. On 1 January 1941 the start of the year moved from April to January, aligning the Thai year with the Western one. The Buddhist Era remains the official calendar today, which is why modern Thai coins carry years in the 2500s.
Questions collectors ask
How do I convert a Thai Buddhist Era year to a Western year?
Subtract 543. BE 2500 is 1957, BE 2517 is 1974. For dates from 1941 on this is exact; for earlier dates the coin may have been struck early in the following Western year, because the Thai year then began on 1 April.
What do the Thai abbreviations before the date mean?
พ.ศ. is the Buddhist Era (subtract 543), ร.ศ. is the Rattanakosin Era (add 1781) and จ.ศ. is the Chula Sakarat (add 638). If there is no abbreviation, a year in the 2400s or 2500s is Buddhist Era, one in the 100s is Rattanakosin and one in the 1100s or 1200s is Chula Sakarat.
What are the Thai numerals?
๐ 0, ๑ 1, ๒ 2, ๓ 3, ๔ 4, ๕ 5, ๖ 6, ๗ 7, ๘ 8, ๙ 9. They are read left to right with the same place values as Western digits.
What year is ร.ศ. 127 on a Thai coin?
1908. The Rattanakosin Era counts from the founding of Bangkok in 1782, so add 1781: 127 + 1781 = 1908.
Why might a Thai coin be one year later than the conversion says?
Before 1941 the Thai year began on 1 April, so each Thai year covered April to the following March. The usual conversion gives the April-to-December year; a coin struck in January to March belongs to the next Western year.
Sources
The calendar rules and their history follow the Wikipedia articles Thai solar calendar, Chula Sakarat and Date and time notation in Thailand. One general article dates the Buddhist Era’s adoption to 1913; the more specific articles give 1912 (BE 2455), which this guide follows.
Related guides
What to record when you buy a coin — including the date as struck, alongside the Western year.
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