Sentence Spacing

Sentence spacing is the horizontal space between sentences in typeset text. It is a matter of typographical convention. Since the introduction of movable-type printing in Europe, various sentence spacing conventions have been used in languages with a Latin-derived alphabet. These include a normal word space (as between the words in a sentence), a single enlarged space, two full spaces, and, most recently in digital media, no space. Although modern digital fonts can automatically adjust a single word space to create visually pleasing and consistent spacing following terminal punctuation, most debate is about whether to strike a keyboard's spacebar once or twice between sentences. Traditionally, two spaces could distinguish from a mid-sentence abbreviation or initials, as in, "He was faster than I. P. Jones was next."

Until the 20th century, publishing houses and printers in many countries used additional space between sentences. There were exceptions to this traditional spacing method—some printers used spacing between sentences that was no wider than word spacing. This was French spacing—a term synonymous with single-space sentence spacing until the late 20th century. With the introduction of the typewriter in the late 19th century, typists used two spaces between sentences to mimic the style used by traditional typesetters. While wide sentence spacing was phased out in the printing industry in the mid-twentieth century, the practice continued on typewriters and later on computers. Perhaps because of this, many modern sources now incorrectly claim that wide spacing was created for the typewriter.

Many experts now say that additional space is not required or desirable between sentences. Typesetting programs such as TeX can modify kerning values to adjust spaces following terminal punctuation, so there is less need to increase spacing manually between sentences (provided that there is some cue to distinguish the end of a sentence from the end of an abbreviated word). From around 1950, single sentence spacing became standard in books, magazines and newspapers, though the recommendation of using 1.5 spaces persisted at least to 1996. Regardless, many still believe that double spaces is correct. The debate continues, notably on the World Wide Web—as many people use search engines to try to find what is correct. Many people prefer double sentence spacing for informal use because that was how they were taught to type. There is a debate on which convention is more readable, but the few recent direct studies conducted since 2002 have produced inconclusive results.

Much modern literature on typography says that double spacing is not desirable, but other sources indicate that it could be used on a typewriter or with a monospaced font. The majority of style guides opt for a single space after terminal punctuation for final and published work, with a few permitting double spacing in draft manuscripts and for specific circumstances based on personal preference. Grammar and design guides, including Web design guides, provide similar guidance.