Dear Dave:

My colleague at work says you’re only supposed to put one space at the end of a sentence before starting another sentence, but I learned you should put two spaces and that’s how I write documents. He’s always changing them. Who’s right?

Signed,

Two Spaces are Better

Dear Two Spaces are Better:

You call this marketing? What are you people doing in your company? Build your brand why don’t you. Generate leads. Help out the sales team.

Okay, the way documents and passages of text appear online and in print is important, and is part of marketing’s domain, but I’ve got some news for you, Two Spaces is Better: one space is better. Let me explain. 

Many of us of a certain age learned our keyboarding skills on good old fashioned typewriters, which allotted the same amount of horizontal space to each letter, whether that letter was an ‘m’ or an ‘i’. Fonts that give each letter the same amount of space are called monospaced fonts.

Courier, which I’m using here, is an example of a monospaced font.  Using an extra space after a sentence, as I do in this passage, helps readers visually identify sentence breaks.  I know, the one space versus two spaces is a small detail, but studies have shown it to be important.  Overall, I’m sure you’d agree this monospaced font is not very appealing.

Most fonts used today on computers are proportional fonts. With proportional fonts, different letters take up different amounts of space. An ‘m’ takes up more space than an ‘i’. You don’t need an extra space after a sentence when using proportional fonts because the software attempts to “fit” the type to specific line lengths, expanding and contracting available space to make the type fit. Word spacing is where most of this space adjustment takes place.  

The other problem with two spaces is that it can contribute to ‘rivers’ of white space that run vertically through a long passage of text and distract the reader.  Justifying both the right and left margins also can lead to this visual problem, because the software sometimes has to add spaces to make sure those pretty margins on both the right and left side are nice and straight.  I’m justifying the left and right margins of this passage, and using two spaces after a period, so you can see how the problem might arise.   Your eyes might be attracted more to the spaces than the words, wreaking havoc on your comprehension of textual meaning.   Try this: pick any space in the first line and see how easy it is to create a visual path down through the lines to the end of the passage.  The other crime I’m committing is italicizing a long passage of text: italics are harder to read than straight-up text.   But you didn’t ask about margin justification and italics, you asked about one or two spaces after a period at the end of a sentence.  One space, period.

Or I should say: period, one space.

For David Klein Marketing, I’m Dave