# Double space between sentences

I've been reading a question on spaces between sentences on a sister site. The answers there seem to imply that the days of double spacing between sentences are over, and that this was a relic of the type-writer and mono-spaced fonts. I was a little surprised by this, so I took a look in two magazines I have at hand: The New Yorker, and The Economist. I was surprised to notice that indeed, it doesn't seem that they use double-space between sentences.

Are we (*TeX users) "behind the times"? Or are we in the right and everyone else is trying to save a space in an inappropriate place? Perhaps this is just laziness of modern type-setters and editors (since they don't use LaTeX...). What is the typesetters' professional opinion about this?

Finally, to make the question relevant to this site: What command will make my documents look like that too (If I wanted so...)? In other words, how to cancel this double-space between sentences, and make the spacing always single space?

Use the \frenchspacing command; that makes the sentence spacing single spaced. You can revert it later on in the document via \nonfrenchspacing.

Personally I don't care either way about the spacing after a full stop. I tend not to notice it when I am reading anyway. I do, however, find that with paper drafts I'm editing, it is easier to visually locate the start/end of a sentence with the extra bit of padding.

It seems to me that the sister site is presenting a false dilemma. Use one space or use two? If those were my only options, I'd definitely opt for one space. Similarly, I only insert one space in my source mark-up. But LaTeX's end-of-sentence space is not the width of two spaces! I'd find it very ugly if it were. It's somewhere in between one and two (and of course, it varies since it's a rubber length.) In my opinion, it looks far nicer and is far less distracting than either having only one space or having two full spaces.

I think the reason this false dilemma is presented this way is that people have given in to the evils of WYSIWYG, so what they type has to be the same as the output. There's no way to type one and a half-space, so they conclude there's no way to get it. Nonsense.

I think people's typographical expectations have declined in the web and WYSIWYG era. I see advocacy of LaTeX as a reaction against this. There's no question that in the digital age, typography needs to change, but let's not let an important and valuable art form die altogether!

• IMO, one interword space plus the space above the period is nearly the optimum for sentence endings. Maybe LaTeX' default mechanism should be used to decrease the spacing after non-sentence-ending periods. – lockstep Oct 30 '10 at 14:32
• I think this is a great answer. Along the same lines, a fellow user ShreevatsaR has added an answer on English.SE to the original question. – Juan A. Navarro Oct 30 '10 at 14:53

Something TeXnical has been omitted from this discussion: how exactly TeX treats space after a period. The details are in The TeXbook, of course, but here's a quick summary.

When TeX is processing a horizontal list of boxes and glue, it uses a number called the space factor f  to decide how much extra space to add and how much to stretch or shrink the glue. At the start of a horizontal list f = 1000. After a period (that doesn't follow a capital letter), f = 3000. After math lists, boxes, and other characters, f = 1000 (capital letters set f = 999).

This parameter is used as follows. When f ≥ 2000, TeX adds the font's "extra space" to the font's "normal space" in the interword glue. After this, the font's "normal stretch" is multiplied by f /1000 and the "normal shrink" is multiplied by 1000/f.

In practice, this means that intersentence spacing has a fixed extra space added and the space can stretch 3 times as much and shrink 1/3 as much as a normal space.

For concreteness, Computer Modern roman 10pt sets
normal space = 3.33333 pt;
normal stretch = 1.66666 pt;
normal shrink = 1.11111 pt; and
extra space = 1.11111 pt.

For example, in a line that has no stretch and no shrink, a space following a period will be 4.44444 pt whereas a space that doesn't follow a period will be 3.33333 pt.

Let's verify these numbers. To do this we make a simple plain TeX file

\setbox0\hbox{ }
\setbox2\hbox{\spacefactor3000{} }
\showthe\wd0
\showthe\wd2
\end


Sure enough, the output shows those values. (The {} after the 3000 is needed because TeX allows optional spaces after numbers. Removing it gives a width of 0 pt.)

Finally, this explains the \@ LaTeX macro which expands to (essentially) \spacefactor1000. Thus in the following code, box 0 will be 1.11111 pt wider than box 2. (Since plain TeX doesn't define \@, we'll do it ourselves.)

\def\@{\spacefactor1000 }
\setbox0\hbox{. }
\setbox2\hbox{.\@ }
\showthe\wd0
\showthe\wd2
\end


One can verify the stretching and shrinking properties as well by putting the text into an \hbox of the appropriate size, but that takes slightly more work and is left as an exercise for the reader.

• This is from LaTeX (plain) is identical. \nonfrenchspacing \def\frenchspacing{\sfcode\.\@m \sfcode\?\@m \sfcode\!\@m \sfcode\:\@m \sfcode\;\@m \sfcode\,\@m} \def\nonfrenchspacing{\sfcode\.3000\sfcode\?3000\sfcode\!3000% \sfcode\:2000\sfcode\;1500\sfcode\,1250 } – Yiannis Lazarides Oct 31 '10 at 2:38

Willie Wong has already provided the TeXnical answer (use \frenchspacing), so I'll only add a quote from Hedrick, Guidelines for Typography in NBCS, p. 9:

Note that typographical experts recommend using a single space after periods or colons. If you add more space, you are emphasizing the sentence break unnecessarily. You will find some authorities that still recommend two spaces. However consensus among typographers is strong.

Bringhurst says (The Elements of Typographic Style, v3.2, pp28-30):

2.1.4 Use a single word space between sentences.

This whole section is actually slightly vitriolic. Referring to the addition of an extra space after a full stop:

Your typing, as well as your typesetting, will benefit from unlearning this quaint Victorian habit.

But there are cases:

The rule is sometimes altered however ... texts in which sentences begin with lowercase letters.

• As I'm the proud owner of Bringhurst v3.1, I'd like to know the changes from v3.1 to v3.2. – lockstep Oct 30 '10 at 13:32
• @lockstep: Sorry, dunno. He hasn't put any revision markers in (:?), and this is my first copy... – Brent.Longborough Oct 30 '10 at 13:35
• 'quaint Victorian habit' - which apparently is false, per the discussion of pre-Victorian typography in heracliteanriver.com/?p=324 – Charles Stewart Jul 25 '13 at 10:43
• @CharlesStewart Well, now, there's food for thought. Thank you. – Brent.Longborough Jul 25 '13 at 17:41
• I don't really care about the loss of two points, but whoever downvoted should share their reasons with us, in the unlikely event they have something to contribute beyond the downvote. – Brent.Longborough Oct 15 '16 at 18:12

tldr; re "the days of double spacing between sentences" being over, I strongly and sincerely hope not. For me, that little extra inter-sentence spacing is, amongst otherwise well-typeset text, a thing of immense beauty that I will fight in my own way, tooth and claw, not to easily lose.

I rather side with Andrew on this, although admittedly, forums like this are not conducive to achieving an ideal answer. For myself, I very much notice text typeset one way and the other. While my response to "singly spaced" inter-sentence gaps isn’t as visceral as when confronted with lining figures in body text (the horror), given the choice I prefer reading non-French style typeset works.

For myself, I see at least three reasons to prefer wide inter-sentence spacing (W) over non-wide than intra-sentence spacing (N). However, before getting to these, can we agree that, unless we're talking about monospaced fonts, TeX/LaTeX typeset "double spaced" inter-sentence gaps are not really two spaces wide. Guesstimating, they median out at around 1.25 normal space widths or so (actual fount depending).

But wait, there’s more. My second argument builds on my first. Reading is a "pyramidal" experience at every level of cognitive processing. Sentences and easily discerning sentence divisions are every bit a part of that. Now I haven’t any idea whether anyone has performed the experiment, but I’m willing to bet a vegemite sandwich that speed readers as well as highly fluent readers when selected equally from populations trained on W and populations trained on N are as a group on average going to have greater efficiency, less staggering, and consequently greater information retention over W than N text. No, I’m not going to dive into the psych databases to find that out. Not even to defend a vegemite sandwich.

My third argument is less prosaic. I have just spent some time sampling the top 10 tier-1 economic journals and all 10 are typeset in the W tradition. Since they’re what I need to read most efficiently, I’ll rest my case on that. I’d certainly be interested in hearing about which style the journals or books from other home disciplines tend to mete out.

The worst part about the double space in tex is that it also appears after the abbreviation dot unless the writer takes special care in order to avoid this. I cannot count how many scientific articles (obviously written in tex) I have read which were otherwise rather well typeset but nonetheless interspersed with this typographical error. Whatever opinion one might have about the larger spacing between sentences – after an abbreviation, it is just plain wrong and sometimes even distracting.

For casual (or unknowing) users this is just too easy to get wrong. So in a sense of giving the average author a tool to write not-too-bad typeset documents, I figure it is ‘behind the times’. It should better be an option to be enabled manually by users who know what they’re doing.

• The TeXbook says: "TEX doesn’t consider a period or question mark or exclamation point to be the end of a sentence if the preceding character is an uppercase letter, since TEX assumes that such uppercase letters are most likely somebody’s initials." It makes me wonder if it's LaTeX that's screwing things up... – morbusg Oct 30 '10 at 16:43
• @morbusg: I don't think that anybody is screwing anything up there. The bad spacing in scientific articles is often seen e.g. after e.g. – Hendrik Vogt Oct 30 '10 at 17:17
• I agree that double-spacing after a (lower case) abbreviation is somewhat offensive (much more so than single-spacing after an upper case sentence-ending abbreviation). I'm not sure that I would blame (la)tex for this. Quality typesetting requires some effort from the compositor. – Lev Bishop Oct 31 '10 at 2:47
• @Hendrik: You get editors? That sounds fantastic. – TH. Oct 31 '10 at 9:04
• You can use ties "e.g.~a fish" or manual spacing "e.g.\, a fish". – Sam Nead Sep 21 '11 at 20:54

I'm in a belligerent mood and so feel like telling the "experts" where to go!

More seriously, I think that there is a big difference between a technical document and a newspaper article. In a technical document, I want Big Signposts breaking it up into manageable chunks. Clearly delimited sentences is one of them. So I disagree strongly that the emphasis of the sentence break is "unnecessary" and would always include them in a technical document.

In an essay, or something else that isn't to be taken seriously (such as an article in the NewYorker or the Economist), then I'd agree that the flow is more important than the content so if people felt that the double spacing broke up the flow, I could understand why they'd take out the spaces (I wouldn't do it myself, though).

(Added in edit): out of curiosity, I did the first lipsum paragraph in each (TeX) style (image below). When seen side by side, I much prefer the extra space. If I had to single out an instance where I think it makes a huge difference, it's the three-word sentence "Mauris ut leo". Without the extra spacing, it gets lost.

(As for rivers, I see more in the smaller-spaced text! Because sentence ends are the same spacing (ish) as inter-word spaces, the potential matches for rivers are thereby increased. In the upper one, big gaps above little gaps don't - for me - create so many rivers.)

• hmmm. Why did you make your answer community wiki? – Yossi Farjoun Oct 30 '10 at 11:15
• @Yossi: because the original question had two parts: a part with a definite answer (how to make double spacing go away), and a part that ought to have been CW as there's no right answer (is double spacing good?). As the question has the two parts, I wasn't sure about hitting it with the wiki-hammer, but as my answer was definitely to the second part, making it CW seemed a reasonable compromise. – Loop Space Oct 30 '10 at 11:18
• @Yossi Farjoun: so I don't feel tempted into down-voting him based on his characterisation of The Economist. ;p @lockstep: tracing out rivers in textbooks was one of the things that made boring high school lectures bearable. Now you take that away from me! – Willie Wong Oct 30 '10 at 11:52
• @lockstep: but the period and space are used after abbreviations, like Prof. so I don't think differentiating the sentence is unnecessary. Also I don't usually take typographers serious on what they say, they tend to exaggerate tiny issues. – Khaled Hosny Oct 30 '10 at 15:53
• @Khaled Hosny: "...exaggerate tiny issues..." -- I think obsessive-compulsive disorder in typographers is either an occupational hazard or a pre-req to getting your licence. Don't know which. – Brent.Longborough Oct 30 '10 at 18:06

I would like to fill in a couple of the gaps from the other answers:

1. the \frenchspacing comes from french typesetting tradition where you put a space before a punctuation: "...faire ? C'est..." (so adding more than one space after the punctuation would look too much). To "opposite" that, then, is to...
2. ... put a slightly longer space after punctuation, in TeX's case a "em-space" IIRC.

One sometimes-important argument for larger inter-sentence space is that when you have an underfull line it's often typographically better to add a bit more space after a sentence rather than space all the words out just that little bit more.

• You can achieve such an effect in tex by setting \fontdimen7\font=0pt (or \xspaceskip=\fontdimen2\font). With the other settings at their defaults, you will get an intersentence space that has the same natural width as an interword space, but 3 times as much stretch and one third as much shrink). – Lev Bishop Oct 31 '10 at 3:49
• Or try \usepackage{microtype} for better results. – koppor Jan 26 '14 at 15:21

My opinion is that \nonfrenchspacing is preferable, but computer modern has excessive values for the parameters. 10pt computer modern makes the intersentence space 1/3 larger than the interword space (it's really 4/3space, not doublespace). Compare this with times, garamond and charter, which only add 1/4 space; minionpro only adds 1/6 space.

This compounds with the abnormally large interword space of computer modern (3.333pt, versus ~2.5pt for times/garamond/charter/minionpro), meaning the increment in intersentence space of computer modern is 2 times as large as times/garamond/charter and 3 times as large as minionpro. I find the more subtle variation in spacing of any of these other fonts preferable to computer modern. The extra space is subtle, but slightly different and noticeably better than \frenchspacing for these fonts. For computer modern I can understand why some people prefer \frenchspacing.

• I think CM's default here reflects its heritage. It's based on 19th-era British typefaces (IIRC), from a period in which very large post-punctuation space was the fashion. – Will Robertson Oct 31 '10 at 7:07

In computer science, the period can mean other things except the end of the sentence: a Lambda term separator (e.g., λ x, y. x+y), function application in some seldom convention (e.g., f.x), choice of a structure component (e.g., car.front_right_wheel), choice of a method (e.g., car.turn_right(90)). So, English spacing simply helps the reader to distinguish between the end of the sentence and other constructions. Whenever I'm tight on space (e.g., in conference proceedings), I use French spacing. Whenever I have space (e.g., in the final versions of journal papers and in some books), I use English spacing.

• Note that "French spacing" means no extra space at the end of sentences, i.e. the inter-sentence space is the same as the inter-word space. – ShreevatsaR Sep 3 at 18:51
• @ShreevatsaR Right. Reversed. – MdAyq6 Sep 3 at 20:33

## protected by lockstepMay 12 '11 at 18:02

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