Thai numerals (เลขไทย) are a set of numerals traditionally used in Thailand, although the Arabic numerals are more common. Thai numerals follow the Hindu-Arabic numeral system commonly used in the rest of the world. In the Thai language, numerals often follow the modified noun and precede a measure word, although variations to this pattern occur.

Main numbers

Zero to nine

The Thai name for zero, which also means center, depending on context, is clearly from Sanskrit śūnya, as are context-driven names for Alternate numbers 2 to 4, given below; but not one or its alternatives. Thai names for regular digits two through nine resemble those in Cantonese as spoken in Southern China, putative homeland of the Tai. Shown below is a comparison between the two languages using Cantonese characters and pronunciations. The Thai transliteration uses the Royal Thai General System of Transcription (RTGS).

Number	Thai		RTGS	Cantonese
0	๐	ศูนย์	sun	(Sanskrit śūnya)
1	๑	หนึ่ง	nueng	-
2	๒	สอง	song	雙 (seung1)
3	๓	สาม	sam	三 (saam1)
4	๔	สี่	si	四 (sei3)
5	๕	ห้า	ha	五 (ng5)
6	๖	หก	hok	六 (luk6)
7	๗	เจ็ด	chet	七 (chat1)
8	๘	แปด	paet	八 (baat3)
9	๙	เก้า	kao	九 (gau2)

Ten to a million

These are assembled from the words for the powers of ten. The number one following a power of ten becomes et (Cantonese: 一, yat¹). The numbers from twenty to twenty nine begin with yi sip (Cantonese: 二十, yi⁶sap⁶). See Alternate numbers.

Number	Thai		RTGS
10	๑๐	สิบ	sip
11	๑๑	สิบเอ็ด	sip et
12	๑๒	สิบสอง	sip song
20	๒๐	ยี่สิบ	yi sip
21	๒๑	ยี่สิบเอ็ด	yi sip et
22	๒๒	ยี่สิบสอง	yi sip song
100	๑๐๐	ร้อย	roi
1 000	๑๐๐๐	พัน	phan
10 000	๑๐๐๐๐	หมื่น	muen
100 000	๑๐๐๐๐๐	แสน	saen
1 000 000	๑๐๐๐๐๐๐	ล้าน	lan

The hundreds are formed by combining roi with the tens and ones values. For example, two hundred and thirty-two is song roi sam sip song. The words roi, phan, muen, and saen occur should with a preceding numeral (nueng is optional), so two hundred and ten, for example, is song roi sip, and one hundred is either roi or nueng roi. Nueng never precedes sip, so song roi nueng sip is incorrect. Native speakers will sometimes use roi nueng (or phan nueng, etc.) with different tones on nueng to distinguish one hundred from one hundred and one. However, such distinction is often not made, and ambiguity may follow. To resolve this problem, if the number 101 (or 1001, 10001, etc.) is intended, one should say roi et (or phan et, muen et, etc.).

Numbers above a million

Numbers above a million are constructed by prefixing lan with a multiplier. For example, ten million is sip lan, and a trillion (10¹²) is lan lan.

Decimal and fractional numbers

Colloquially, decimal numbers are formed by saying จุด (chut, dot) where the decimal separator is located. For example, 1.01 is หนึ่งจุดศูนย์หนึ่ง.

Fractional numbers are formed by placing ใน (nai, in, of) between the numerator and denominator. For example, ⅓ is หนึ่งในสาม (neung nai sam).

The word ครึ่ง (khrueng) is used for "half". It precedes the measure word if used alone, but it follows the measure word when used with another number. For example, kradat krueng phaen (กระดาษครึ่งแผ่น) means "half sheet of paper", but kradat nueng phaen krueng (กระดาษหนึ่งแผ่นครึ่ง) means "one and a half sheets of paper".

Negative numbers

Negative numbers are formed by placing ลบ (lop, minus) in front of the number. For example, -11 is ลบสิบเอ็ด (lop sip et).

Ordinal numbers

Ordinal numbers are formed by placing ที่ (thi, place) in front of the number. They are not considered a special class of numbers, since the numeral still follows a modified noun, which is thi in this case.

Thai	RTGS	meaning
ที่หนึ่ง	thi nueng	first
ที่สอง	thi song	second
ที่สาม	thi sam	third
ที่สี่	thi si	fourth
ที่#	thi #	#st, #nd, #rd, #th

Alternate numbers

Aai

Aai (อ้าย), means first born (son) or Moon 1 Online Royal Institute Dictionary (ORID)

Et

Et (เอ็ด, Cantonese: 一, yat¹), means one, and is used as last member in a compound number (see above).

Yi

Yi (ยี่, Cantonese: 二, yi⁶) is still used in several places in Thai language for the number 2, apart from สอง (song). For example, Yi is used instead of song to construct 20 (2 tens) and its combinations 21-29. Yi is still used to name the second month of the traditional Thai lunar calendar, and in the Thai northern dialect (TH: ถิ่น–พายัพ) refers to the Year of the tiger, (ORID)

Yip

Yip (ยีบ) in colloquial Thai is an elision of ยี่สิบ (yi sip) at the beginning of numbers 21 through 29; therefore, one may hear ยีบเอ็ด (yip et), ยีบสอง (yip song), etc.

Sow

Sow (ซาว) means 20 in the Thai northern dialect, according to the ORID; it is also frequently heard in Isan in the expression sow baht for 20 baht.

Tri-

Tri- (ไตร-) is a prefix meaning three(fold).

Tone marks, education degrees and military ranks

The alternate set of numerals used to name tonal marks (ไม้, mai), educational degrees (ปริญญา, parinya), and military rankings derive from names of Sanskrit numerals.

Number			Tonal Mark				Educational Degree			Military Ranking in the Royal Thai Army
Thai	RTGS	Value	Mark	Thai	RTGS	Tone	Thai	RTGS	Degree	Thai	RTGS	Meaning
เอก	ek	first	-่	ไม้เอก	mai ek	first tone	ปริญญาเอก	parinya ek	doctor's	พลเอก	phon ek	General
										พันเอก	phan ek	Colonel
										ร้อยเอก	roi ek	Captain
										จ่าสิบเอก	cha sip ek	Master Sgt. 1st Class
										สิบเอก	sip ek	Sergeant (Sgt.)
โท	tho	second	-้	ไม้โท	mai tho	second tone	ปริญญาโท	parinya tho	master's	พลโท	phon tho	Lieutenant General
										พันโท	phan tho	Lieutenant Colonel
										ร้อยโท	roi tho	Lieutenant
										จ่าสิบโท	cha sip tho	Master Sgt. 2nd Class
										สิบโท	sip tho	Corporal
ตรี	tri	third	-๊	ไม้ตรี	mai tri	third tone	ปริญญาตรี	parinya tri	bachelor's	พลตรี	phon tri	Major general
										พันตรี	phan tri	Major
										ร้อยตร	roi tri	Sub Lieutenant
										จ่าสิบตรี	cha sip tri	Master Sgt. 3rd Class
										สิบตรี	sip tri	Lance Corporal
จัตวา	chattawa	fourth	-๋	ไม้จัตวา	mai chattawa	fourth tone				พลจัตวา	phon chattawa	Brigadier General (Honorary)

See also

• Thai language
• Thai alphabet
• Thai six-hour clock
• Chinese numerals
• The Royal Institute of Thailand

External links

• Thai Royal Institute On-line Dictionary (ORID 1999) [TH: พจนานุกรม ฉบับราชบัณฑิตยสถาน พ.ศ. ๒๕๔๒]