Thai numerals (Thai:เลขไทย,RTGS: lek thai,pronounced[lêːktʰāj]) are a set of numerals traditionally used inThailand, although theArabic numerals are more common due to extensivewesternization of Thailand in the modernRattanakosin period. Thai numerals follow theHindu–Arabic numeral system commonly used in the rest of the world. In Thai language, numerals often follow the modified noun and precede a measure word, although variations to this pattern occur.

TheThai language lacksgrammatical number. Acount is usually expressed in the form of anuninflected noun followed by a number and a classifier. "Five teachers" is expressed as "teacher five person"khru ha khon (Thai:ครูห้าคน or with the numeral includedThai:ครู ๕ คน.)Khon "person" is a type ofreferent noun that is also used as the Thaipart of speech called in English alinguistic classifier, ormeasure word. In Thai, counting iskannap (การนับ;nap is "to count",kan is a prefix that forms a noun from a verb); the classifier,laksananam (ลักษณนาม fromlaksana characteristic, form, attribute, quality, pattern, style; andnam name, designation, appellation.^[1]) Variations to this pattern do occur, and there really is nohierarchy among Thai classifiers.^[2]A partial list of Thai words that also classify nouns can be found in Wiktionary category:Thai classifiers

Thaisūn (zero) is written as oval0 (number) when using Arabic numerals, but a small circle๐ when using traditional numerals, and also meanscentre in other contexts.^[3] It is fromSanskritśūnya, as are the (context-driven)alternate names for numbers one to four given below; but not the counting1 (number).

Thai names forN +1^{[clarification needed]} and the regular digits 2 through 9 as shown in the table, below, resemble those inChinese varieties (e.g.,Cantonese andMin Nan) as spoken inSouthern China, the homeland of the overseas Chinese living in South East Asia. In fact, the etymology of Thai numerals 2, 3, 4, 6, 7, 8, 9, and 10 isMiddle Chinese, while the etymology of Thai numeral 5 isOld Chinese, as illustrated in the table below.^[4]

Numerical digit characters, however, are almost identical toKhmer numerals. Thai and Lao words for numerals are almost identical, however, the numerical digits vary somewhat in shape. Shown above is a comparison between three languages usingCantonese andMinnancharacters and pronunciations. Shown below is a comparison between three languages usingKhmer numerals: Thai, Khmer, and Lao. The Thaitransliteration uses theRoyal Thai General System of Transcription (RTGS).

Sanskritlakh designates theplace value of a digit (tamnaeng khong tua lek, ตําแหน่งของตัวเลข), which are named for the powers of ten: the unit's place islak nuai (หลักหน่วย); ten's place,lak sip (หลักสิบ); hundred's place,lak roi (หลักร้อย), and so forth.^[5] The number one following any multiple ofsip becomeset (Cantonese: 一, yat¹; Minnan: 一, it⁴). The number ten (sip) is the same as Literary Hokkien 十 (si̍p). Numbers from twenty to twenty nine begin withyi sip (Cantonese: 二十 (yi⁶sap⁶); Hokkien: 二十 (lī-cha̍p / jī-cha̍p / gī-cha̍p); Teochew: 二十 (jĭ tsa̍p)). Names of thelak sip for 30 to 90, and for thelak of 100, 1000, 10,000, 100,000 and million, are almost identical to those of the likeKhmer numerals.

For the numbers twenty-one through twenty-nine, the part signifying twenty:yi sip (ยี่สิบ), may be colloquiallyshortened toyip (ยีบ).^{[citation needed]} See the alternate numbers section below.

The hundreds are formed by combiningroi with the tens and ones values. For example, two hundred and thirty-two issong roi sam sip song. The wordsroi,phan,muen, andsaen should occur with a preceding numeral (nueng is optional), so two hundred ten, for example, issong roi sip, and one hundred is eitherroi ornueng roi.Nueng never precedessip, sosong roi nueng sip is incorrect. Native speakers will sometimes useroi nueng (orphan nueng, etc.) with different tones onnueng 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 sayroi et (orphan et,muen et, etc.).

Numbers above a million are constructed by prefixinglan with a multiplier. For example, ten million issip lan, and a trillion (10¹², a long scalebillion) islan lan.

Colloquially, decimal numbers are formed by sayingchut (จุด, dot) where thedecimal separator is located. For example, 1.01 isnueng chut sun nueng (หนึ่งจุดศูนย์หนึ่ง).

Fractional numbers are formed by placingnai (ใน, in, of) between the numerator and denominator or using[set] x suan y ([เศษ] x ส่วน y, x parts of the whole y) to clearly indicate. For example,1⁄3 isnueng nai sam (หนึ่งในสาม) or[set] nueng suan sam ([เศษ]หนึ่งส่วนสาม). The wordset (เศษ) can be omitted.

The wordkhrueng (ครึ่ง) 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 khrueng phaen (กระดาษครึ่งแผ่น) means "half sheet of paper", butkradat nueng phaen khrueng (กระดาษหนึ่งแผ่นครึ่ง) means "one and a half sheets of paper".

Negative numbers are formed by placinglop (ลบ, minus) in front of the number. For example, −11 islop sip et (ลบสิบเอ็ด).

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

Ai (Thai:อ้าย) is used for "first born (son)" or for the first month,duean ai (เดือนอ้าย), of theThai lunar calendar.^[6]

Ek (Thai:เอก) is from Paliḗka, "one"^[7]Ek is used forone (quantity);first (rank), more prominent thantho โทsecond, intone marks, education degrees and military ranks; and for the lead actor in a role. In antiquity, a seventh daughter was calledluk ek (ลูกเอก), though a seventh son wasluk chet (ลูกเจ็ด).^[8]

Et (Thai:เอ็ด, Cantonese: 一, jat¹; Minnan: 一, it⁴), meaning "one", is used as last member in a compound number (see the main numbers section above).

Tho (Thai:โท) is from Palidūā, "two".^[9]Tho is used fortwo and for thesecond-level rank intone marks, education degrees and military ranks.^[10]

Yi (Thai:ยี่, Cantonese: 二, ji⁶; Minnan: 二, ji⁷) is still used in several places in Thai language for the number two, apart fromsong (สอง): to construct twenty (two tens) and its combinations twenty-one through twenty-nine; to name the second month,duean yi (เดือนยี่), of the traditionalThai lunar calendar; and in the Thai northern dialectthin pha yap (ถิ่นพายัพ), in which it refers to theYear of the Tiger.^[11]

Tri (ตรี) andtrai (ไตร) are from Sanskrittrāyaḥ, "three".^[12] These alternatives are used forthree;third rank intone marks, education degrees and military ranks; and as a prefix meaningthree(fold).^[13]

Chattawa (จัตวา) is thePali numeral four; used for the fourth tone mark and as a prefix meaning fourth in order or quadruple in number.

Lo (Thai:โหล) means adozen or twelve. It is usually used fortrade. It may also mean jar or bottle.^[14]

Yip (Thai:ยีบ or ยิบ) in colloquial Thai is anelision orcontraction ofyi sip (ยี่สิบ) at the beginning of numbers twenty-one through twenty-nine. Therefore, one may hearyip et (ยีบเอ็ด, ยิบเอ็ด),yip song (ยีบสอง, ยิบสอง), up toyip kao (ยีบเก้า, ยิบเก้า).Yip may have a long vowel (ยีบ) or be elided further into a short vowel (ยิบ).

Sao (Thai:ซาว) is twenty in theThai northern dialect^[15] and in theIsan language. It is related toxao (ຊາວ), the word for twenty in theLao language.

Kurut (Thai:กุรุส) means a dozen dozen or 144. It is usually used for trade. It is aloanword fromgross.^[16]

Kot (Thai:โกฏิ) is ten million used in religious context. It comes from Pali/Sanskritkōṭi.^[17] See alsocrore.

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

• Chinese numerals
• Indian numbering system
• Indian numerals
• Khmer numerals
• Lakh
• Thai alphabet
• Thai language
• Thai six-hour clock
• The Royal Institute of Thailand

• Thai Royal Institute On-line Dictionary (ORID 1999) [TH: พจนานุกรม ฉบับราชบัณฑิตยสถาน พ.ศ. ๒๕๔๒]
• Numerals in many different writing systems, which includes Lao, Khmer and Thai numerals 0-9; retrieved 2008-11-12
• Graphic version of Numerals in many different writing systems, no Unicode required; retrieved 2008-11-12
• Thai Numbers. How they are written in their numeral and textual forms and how to pronounce them.
• Search result fornumerative noun (11 entries)
• "International Reference Library Thread of Thai Classifiers" (38 entries)

• Culture of Thailand
• Thai language
• Numerals

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