Unit systemimperial/US units
Unit oflength
1 in in ...... is equal to ...
   imperial/US units   1/36 yd
1/12 ft
   metric (SI) units   25.4 mm

The inch (abbreviation: in or ) is a unit of length in the (British) imperial and United States customary systems of measurement. It is equal to ​136 yard or ​112 of a foot. Derived from the Roman uncia ("twelfth"), the word inch is also sometimes used to translate similar units in other measurement systems, usually understood as deriving from the width of the human thumb. Standards for the exact length of an inch have varied in the past, but since the adoption of the international yard during the 1950s and 1960s it has been based on the metric system and defined as exactly 2.54 cm.


The English word "inch" (Old English: ynce) was an early borrowing from Latin uncia ("one-twelfth; Roman inch; Roman ounce") not present in other Germanic languages.[1] The vowel change from Latin /u/ to Old English /y/ (which became Modern English /ɪ/) is known as umlaut. The consonant change from the Latin /k/ (spelled c) to English /tʃ/ is palatalisation. Both were features of Old English phonology; see Phonological history of Old English § Palatalization and Germanic umlaut § I-mutation in Old English for more information.

"Inch" is cognate with "ounce" (Old English: ynse), whose separate pronunciation and spelling reflect its reborrowing in Middle English from Anglo-Norman unce and ounce.[2]

In many other European languages, the word for "inch" is the same as or derived from the word for "thumb", as a man's thumb is about an inch wide (and this was even sometimes used to define the inch[citation needed]). Examples[citation needed] include Afrikaans: duim; Catalan: polzada ("inch") and polze ("thumb"); Czech: palec ("thumb"); Danish and Norwegian: tomme ("inch") tommel ("thumb"); Dutch: duim; French: pouce; Hungarian: hüvelyk; Italian: pollice; Portuguese: polegada ("inch") and polegar ("thumb"); Slovak: palec ("thumb"); Spanish: pulgada ("inch") and pulgar ("thumb"); and Swedish: tum ("inch") and tumme ("thumb") and Russian: дюйм ("duim").

Other Languages
Afrikaans: Duim
Ænglisc: Ynce
العربية: بوصة
asturianu: Pulgada
বাংলা: ইঞ্চি
башҡортса: Дюйм
беларуская: Цаля
беларуская (тарашкевіца)‎: Цаля
български: Инч
bosanski: Inč
brezhoneg: Meutad
català: Polzada
Чӑвашла: Дюйм
čeština: Palec (jednotka)
Cymraeg: Modfedd
dansk: Tomme
Ελληνικά: Ίντσα
español: Pulgada
Esperanto: Colo
euskara: Hazbete
فارسی: اینچ
français: Pouce (unité)
Gaelg: Oarlagh
galego: Polgada
한국어: 인치
հայերեն: Դյույմ
हिन्दी: इंच
Bahasa Indonesia: Inci
עברית: אינץ'
ಕನ್ನಡ: ಅಂಗುಲ
ქართული: დუიმი
қазақша: Дюйм
Kiswahili: Inchi
Kreyòl ayisyen: Pous (mezi)
kurdî: Înç
latviešu: Colla
lietuvių: Colis
Lingua Franca Nova: Diton (unias de mesura)
македонски: Инч
मराठी: इंच
მარგალური: დუიმი
Bahasa Melayu: Inci
монгол: Инч (нэгж)
Nederlands: Inch
日本語: インチ
norsk nynorsk: Tomme
occitan: Poce (unitat)
oʻzbekcha/ўзбекча: Dyuym
ਪੰਜਾਬੀ: ਇੰਚ
پنجابی: انچ
Piemontèis: Pòles
polski: Cal
português: Polegada
română: Țol
русский: Дюйм
Scots: Inch
shqip: Inçi
Simple English: Inch
سنڌي: انچ
slovenščina: Palec
کوردی: ئینچ
српски / srpski: Инч
srpskohrvatski / српскохрватски: Inč
suomi: Tuuma
svenska: Tum
Tagalog: Dali (haba)
தமிழ்: அங்குலம்
తెలుగు: అంగుళం
Türkçe: İnç
українська: Дюйм
اردو: پور
Tiếng Việt: Inch
Võro: Toll
Winaray: Pulgada
吴语: 英寸
中文: 英寸