Non-breaking space

In word processing and digital typesetting, a non-breaking space ( ), also called NBSP, required space, hard space, or fixed space (in most typefaces, it is not of fixed width), is a space character that prevents an automatic line break at its position. In some formats, including HTML, it also prevents consecutive whitespace characters from collapsing into a single space. Non-breaking space characters with other widths also exist.

Despite having layout and uses similar to those of whitespace, it differs in contextual behavior.

Text-processing software typically assumes that an automatic line break may be inserted anywhere a space character occurs; a non-breaking space prevents this from happening (provided the software recognizes the character).

For example, if the text "100 km" will not quite fit at the end of a line, the software may break the line between "100" and "km". Using a non-breaking space between "100" and "km" will prevent this behaviour. This guarantees that the text "100 km" will not be broken—if it does not fit at the end of a line, it is moved in its entirety to the next line. For this reason, many style guides recommend using a non-breaking space between numbers and their associated units.

In French typography, non-breaking spaces are used before "high punctuation" (:, ;, ?, and !), on the interior side of guillemets (« and »), and before footnotes. In the case of ;, ?, !, and footnotes (unless enclosed by parentheses), it is specifically the narrow non-breaking space that is used.

In German typography, it is used between multi-part abbreviations (e.g., "z. B.", "d. h.", "v. l. n. r.").

A second common application of non-breaking spaces is in plain text file formats such as SGML, HTML, TeX and LaTeX, whose rendering engines are programmed to treat sequences of whitespace characters (space, newline, tab, form feed, etc.) as if they were a single character (but this behavior can be overridden). Such "collapsing" of whitespace allows the author to neatly arrange the source text using line breaks, indentation and other forms of spacing without affecting the final typeset result.

In contrast, non-breaking spaces are not merged with neighboring whitespace characters when displayed. They can, therefore, be used by an author to simply insert additional visible space in the resulting output without using spans styled with peculiar values of the CSS "white-space" property. Conversely, indiscriminate use (see the recommended use in style guides), in addition to a normal space, gives extraneous space in the output.

U+202F  NARROW NO-BREAK SPACE (NNBSP) is another non-breaking space, but with a smaller width than the standard non-breaking space (U+00A0). When used with Mongolian, its width is usually one third of the normal space; in other contexts, its width is about 70% of the normal space, but may resemble that of the thin space (U+2009), at least with some fonts.

It was introduced in Unicode 3.0 for Mongolian, to separate a suffix from the word stem without indicating a word boundary. It also triggers special shaping of those suffixes. Starting in Unicode 16.0, it is no longer recommended for this purpose, with the Mongolian vowel separator (U+180E) being recommended for this purpose instead.

In French typography, it is called espace fine insécable and is used before ;, ?, and !. Additionally, footnotes are preceded by a narrow non-breaking space (unless they are enclosed by parentheses, in which case a regular non-breaking space is used).

The narrow non-breaking space is used in numbers as a group separator in French (starting in Unicode CLDR 34) and Venetian (starting in Unicode CLDR 44). In Spanish, the Royal Spanish Academy and Association of Academies of the Spanish Language's Diccionario panhispánico de dudas proscribes the use of a small space as the number group separator, although this is not the case in Unicode's Common Locale Data Repository (CLDR).

Other non-breaking variants defined in Unicode.

U+2007  FIGURE SPACE ( )

Produces a space equal to the figure (0–9) characters.

U+2060 WORD JOINER (⁠ · WJ)

Encoded in Unicode since version 3.2. The word joiner does not produce any space and prohibits a line break at its position.

On browsers, resizing the window will demonstrate the effect of non-breaking spaces on the texts below.

To show the non-breaking effect of the non-breaking space, the following words have been separated with non-breaking spaces:

To show the non-collapsing behavior of the non-breaking space, the following words have been separated with an increasing number of non-breaking spaces:

In contrast, the following words are separated with ordinary spaces:

Here, they are separated with narrow non-breaking spaces, to show the width of those:

• U+00A0   NO-BREAK SPACE ( ,  )
• U+2007  FIGURE SPACE ( )
• U+202F  NARROW NO-BREAK SPACE
• U+2060 WORD JOINER (⁠)

• Hyphens in computing, for information about hard and non-breaking hyphens
• List of XML and HTML character entity references
• Non-breaking hyphen – Punctuation mark used to join words
• Punctuation – Marks to indicate pacing of written text
• Sentence spacing in digital media – Horizontal width of inter-sentence space
• Space (punctuation) – Blank area that separates text
  • Space (punctuation) § Non-breaking space, for applications
  • Zero-width space – Special character in text processing, a non-spacing break
• Widows and orphans – In typography, an isolated line of text starting/ending a page
• Non-printing character in word processors – Formatting marks for content design
• Typographic alignment § Justified