How do I type the ＿ fullwidth low line symbol?

On Windows, type FF3F and press Alt+X. On Linux press Ctrl+Shift+U then ff3f. On any system the quickest route is the copy button on this page.

What is the code for ＿?

Fullwidth Low Line is U+FF3F. In UTF-8 it takes 3 bytes. The table above lists every escape format.

Will ＿ survive being pasted anywhere?

Not always. Fullwidth Low Line is a compatibility character: any system that applies Unicode NFKC normalisation — search indexes, usernames, identifiers — replaces it with _. Use it for display, not where text is normalised.

U+FF3F · Connector punctuation

Fullwidth Low Line Symbol ＿

＿ is fullwidth low line, U+FF3F. Unicode records it as a compatibility form of _ (wide form). It was added in Unicode 1.1, and Unicode files it under Connector punctuation.

Also known as

Unicode 1.0 called this character fullwidth spacing underscore. The standard renamed it later, but documents, fonts and font-editing tools from that era still use the old name.

Codes & technical data

Unicode	`U+FF3F`
HTML hex	`＿`
HTML decimal	`＿`
CSS	`\FF3F`
JavaScript	`\u{FF3F}`
Python	`\U0000FF3F`
Java / C#	`\uFF3F`
Rust	`\u{ff3f}`
Swift	`\u{FF3F}`
PHP	`\u{FF3F}`
URL encoded	`%EF%BC%BF`
UTF-8 bytes	`EF BC BF`
UTF-16 bytes	`FF3F`
Base64	`77y/`
Decimal	`65343`
Decomposes to	_ (wide form)
Category	Connector punctuation (Pc)
Introduced	Unicode 1.1

Will ＿ survive being pasted?

Normalisation. No. Anything that applies NFKC — search indexes, usernames, domain names, programming identifiers — rewrites ＿ as _. Safe for display, not for storage.
Legacy encodings. ＿ is Unicode-only — it has no Latin-1 equivalent, so a system stuck on an 8-bit encoding cannot represent it.
Size. 3 bytes in UTF-8. Character-limited fields — SMS, bios, some form validators — usually count bytes, not characters.

Other line characters

Unicode names 6 characters ending in “line”. They differ by direction, weight or decoration rather than by meaning.

Nearby in Halfwidth and Fullwidth Forms

Latin characters at the width of a CJK ideograph, and katakana at half width — a compatibility block for legacy East Asian encodings. Fullwidth text is often used online for a spaced-out aesthetic; it normalises straight back to ASCII.

All 53 characters in Halfwidth and Fullwidth Forms →

How to type ＿

Windows	Type `FF3F` then press `Alt`+`X`
macOS	Press `Ctrl`+`Cmd`+`Space`, then search for “fullwidth low line”
Linux	Press `Ctrl`+`Shift`+`U`, type `ff3f`, press `Enter`
HTML	`＿`

About Unicode’s Connector punctuation category

This is connector punctuation — it joins words rather than separating them, which is why programming languages usually allow it inside identifiers where a hyphen is not allowed.

Frequently asked questions

How do I type the ＿ fullwidth low line symbol?: On Windows, type FF3F and press Alt+X. On Linux press Ctrl+Shift+U then ff3f. On any system the quickest route is the copy button on this page.
What is the code for ＿?: Fullwidth Low Line is U+FF3F. In UTF-8 it takes 3 bytes. The table above lists every escape format.
Will ＿ survive being pasted anywhere?: Not always. Fullwidth Low Line is a compatibility character: any system that applies Unicode NFKC normalisation — search indexes, usernames, identifiers — replaces it with _. Use it for display, not where text is normalised.