Halfwidth and Fullwidth Forms (Unicode block)

{{Infobox Unicode block

|blockname = Halfwidth and Fullwidth Forms

|rangestart = FF00

|rangeend = FFEF

|script1 = {{nowrap|Hangul (52 char.)}}

|script2 = {{nowrap|Katakana (55 char.)}}

|script3 = {{nowrap|Latin (52 char.)}}

|script4 = {{nowrap|Common (66 char.)}}

|symbols = Variant width characters

|1_0_0 = 216

|1_1 = 7

|3_2 = 2

|note = {{cite web|url=https://www.unicode.org/versions/Unicode1.0.0/Notice.pdf|title=Unicode 1.0.1 Addendum|work=The Unicode Standard|date=1992-11-03|access-date=2016-07-09}}{{cite web|url=https://www.unicode.org/ucd/|title=Unicode character database|work=The Unicode Standard|access-date=2023-07-26}}{{cite web|url=https://www.unicode.org/versions/enumeratedversions.html|title=Enumerated Versions of The Unicode Standard|work=The Unicode Standard|access-date=2023-07-26}}

}}

Halfwidth and Fullwidth Forms is a Unicode block U+FF00–FFEF, provided so that older encodings containing both halfwidth and fullwidth characters can have lossless translation to/from Unicode. It is the second-to-last block of the Basic Multilingual Plane, followed only by the short Specials block at U+FFF0–FFFF. Its block name in Unicode 1.0 was Halfwidth and Fullwidth Variants.{{cite web |url=https://www.unicode.org/versions/Unicode1.0.0/CodeCharts2.pdf |work=The Unicode Standard |version=version 1.0 |title=3.8: Block-by-Block Charts |publisher=Unicode Consortium}}

Range U+FF01–FF5E reproduces the characters of ASCII 21 to 7E as fullwidth forms. U+FF00 does not correspond to a fullwidth ASCII 20 (space character), since that role is already fulfilled by U+3000 "ideographic space".

Range U+FF61–FF9F encodes halfwidth forms of katakana and related punctuation in a transposition of A1 to DF in the JIS X 0201 encoding – see half-width kana.

The range U+FFA0–FFDC encodes halfwidth forms of compatibility jamo characters for Hangul, in a transposition of their 1974 standard layout. It is used in the mapping of some IBM encodings for Korean, such as IBM code page 933, which allows the use of the Shift Out and Shift In characters to shift to a double-byte character set.{{cite web|url=http://demo.icu-project.org/icu-bin/convexp?conv=ibm-933|title=ICU Demonstration - Converter Explorer|website=demo.icu-project.org|access-date=7 May 2018}} Since the double-byte character set could contain compatibility jamo, halfwidth variants are needed to provide round-trip compatibility.{{Cite web|url=https://harjit.moe/hwfwblame.html|title=Halfwidth and Fullwidth blame}}{{Cite web|url=http://userguide.icu-project.org/conversion/data|title=Conversion Data - Old location of the ICU User Guide}}

Range U+FFE0–FFEE includes fullwidth and halfwidth symbols.