Two Spaces After a Period: The Hill I Will Die On

I’m going to say something controversial in the year 2026, and I don’t care who it offends: You should put two spaces after a period.

There. I said it. Come at me.

The “One Space” Coup

Somewhere around 2010, the internet collectively decided that two spaces after a period was an anachronism. A relic of the typewriter era. Something your typing teacher made you do because monospace fonts needed the visual break, but proportional fonts rendered it unnecessary.

This narrative is wrong, and I suspect it was propagated by people who skim content rather than read it.

The argument goes like this: typewriters used monospace fonts, so you needed two spaces to visually separate sentences. Modern proportional fonts handle sentence boundaries with kerning and slightly wider period-space combinations, so the extra space is redundant.

Here’s the problem with that argument: I read technical documentation all day. SQL scripts. Code comments. Markdown files. Git commit messages. Terminal output. Half my professional life is spent in monospace, and the other half is spent in proportional fonts that do a terrible job of signaling sentence boundaries in dense, abbreviation-heavy prose.

Why It Actually Matters

Consider this paragraph in a typical DBA’s workday:

Check the value of max_server_memory (MB) in sp_configure. It should be set to approx. 80% of total RAM. See KB article no. 2663 for details. The default is 2147483647 MB which means SQL Server will consume all available memory.

With one space after each period, your brain has to do extra work to distinguish sentence boundaries from abbreviation periods. “approx. 80%” – is that a new sentence? “no. 2663” – did a sentence just end? Your visual cortex processes these micro-ambiguities unconsciously, but they add up. Two spaces after a sentence-ending period eliminates the ambiguity entirely.

Studies back this up. Research from Skidmore College (Johnson, Bui, & Schmitt, 2018) found that two-spacers read text with two spaces faster than text with one space. The effect was small but measurable, and it was specific to people who already used two spaces – their brains had learned to use that wider gap as a sentence-boundary signal.

“But My Style Guide Says…”

Yes, APA switched to one space in their 7th edition. Chicago Manual of Style recommends one space. Every web typography guide written after 2005 says one space.

You know what else style guides recommended? Putting two spaces after a colon. Using Oxford commas consistently. Not starting sentences with conjunctions. Style guides are descriptive of current fashion, not prescriptive laws of readability.

The one-space convention won because:

1. HTML collapses multiple spaces – so web content displays one space regardless of what you type
2. Word processors auto-format – younger writers never learned the distinction
3. Social proof – once enough people stopped doing it, it looked “old-fashioned” to continue

None of these are readability arguments. They’re convenience arguments dressed up as typography arguments.

The Monospace Argument is Backwards

People say “two spaces was for monospace; we don’t need it now.” I’d argue the opposite: proportional fonts need two spaces MORE than monospace does.

In monospace, every character occupies the same width. A period followed by a space is visually distinct because the fixed-width grid creates natural rhythm. You can parse sentence boundaries from the cadence of the text alone.

In proportional fonts, a period is a tiny dot followed by a thin space. It looks identical to an abbreviation period. The proportional font has reduced the visual signal, not enhanced it. The extra space compensates for what proportional rendering takes away.

What I Actually Do

Every document I write uses two spaces after sentence-ending periods. My SQL scripts. My Markdown. My PR reviews. My blog posts (yes, including this one – check the source).

For code, I don’t care – return x; doesn’t need two spaces before a comment on the next line. But for prose? For anything a human being is going to actually read as connected sentences? Two spaces. Always.

I’ve configured my AI assistant to do the same. When it writes Markdown for me, it uses two spaces after periods. When it drafts PR review comments, two spaces. It’s not hard to be consistent about this.

The Real Question

Ask yourself: when was the last time you read something and thought “wow, those two spaces after the period are really distracting and hurting my reading experience”?

Never. That has never happened to anyone. The worst case for two spaces is that you don’t notice them. The best case is that your brain unconsciously uses them as sentence-boundary markers and you read faster.

Now ask: when was the last time you had to re-read a sentence because you couldn’t immediately tell where one sentence ended and the next began in a wall of dense technical text?

If you write or read technical content, this happens constantly. Two spaces fixes it.

The Bottom Line

Use two spaces after a period. Not because a typing teacher told you to. Not because of monospace fonts. Because it makes dense, technical prose easier to parse, and the “arguments” against it amount to “web browsers ignore it anyway” and “it looks old.”

Neither of those is a readability argument. And readability is the only thing that matters.

Agree? Disagree? Tell me I’m wrong on Bluesky or LinkedIn. I’ll be over here, putting two spaces after my periods like a civilized person.