The 8th-Grade Rule: Why Simpler Copy Sells More

There’s a rule of thumb in copywriting that you should write at an 8th-grade reading level, and almost everyone who hears it for the first time bristles a little. It sounds like an insult to the audience. My customers are engineers, people say, or doctors, or lawyers. They read dense material all day. Surely I don’t need to write for them like they’re fourteen.

But the rule was never about intelligence. It’s about attention, and about where reading effort goes.

Reading anything costs effort, and the reader pays that cost from a fixed budget. Every long sentence, every abstract noun, every word that makes them pause charges against it. What matters is what the effort buys. When a doctor reads a journal article, the effort goes into the ideas, and the doctor pays gladly because the ideas are the point. When the same doctor reads your landing page, there are no hard ideas, or there shouldn’t be. So any effort your prose demands is spent purely on decoding you. You’re charging a tax and delivering nothing for it. Smart readers don’t push through such writing out of respect for its sophistication. They’re precisely the ones who recognize that it isn’t worth decoding, and they leave.

That’s the first half of the argument. The second half is about the conditions under which web copy actually gets read. Nobody reads a landing page in an armchair with coffee. They read it on a phone, standing up, in the ninety seconds between other things, with the mental state of someone skimming. Reading level formulas, crude as they are, mostly measure two things: sentence length and word length. Both are proxies for how much a reader must hold in their head at once. A forty-word sentence asks the reader to keep the beginning suspended in memory until the end arrives. On a phone, mid-skim, that suspension fails. The sentence collapses, the reader loses the thread, and losing the thread twice on the same page is usually the end of the visit. The 8th-grade rule is really a working-memory rule. It says: never make a distracted person hold more than one idea in the air.

There’s a status dynamic that keeps people from following the rule, and it’s worth naming, because it’s the actual obstacle. Complicated writing feels impressive to produce. When you write “we leverage proprietary methodologies to optimize outcomes,” you feel like a serious company. When you write “we find what’s slowing your site down and tell you how to fix it,” you feel exposed. Simple sentences have nowhere to hide. If the claim is weak, a simple sentence shows it immediately, whereas jargon can dress up an empty claim for years. This is why simple writing is harder, not easier. It requires you to actually have something to say, and to commit to it in words anyone can check.

The word “sells” in this essay’s title is doing real work, so let me defend it. Selling, at bottom, is transferring conviction. Conviction transfers through understanding; nobody is persuaded by a sentence they only half-parsed. And there’s a subtler effect: prose that reads easily gets trusted more. When a sentence goes down without friction, the claim inside it feels more likely to be true. You can call that a bug in human cognition, and maybe it is, but it also reflects something real. People who understand their subject deeply tend to explain it simply, so simplicity is weak evidence of mastery, and readers have learned to treat it that way. Clear copy doesn’t just communicate better. It signals better.

When I built GazeSite, I made readability one of the six things it grades, and I gave its imagined reader a deliberately unflattering description: skimming, on a phone, at an 8th-grade reading level. Some users push back on that framing, for the same reasons people push back on the rule itself. But the framing isn’t a claim about who their customers are. It’s a claim about what state their customers are in when they arrive. The most brilliant reader on earth is, for the first ninety seconds on your page, functionally a distracted skimmer. Write for the state, not the resume.

The practical version of all this is short. Take your page and read it aloud. Every place you stumble, a visitor stumbles harder. Break any sentence that made you take a breath in the middle. Replace every word you’d never say to a customer’s face across a table. What you’ll end up with will look almost embarrassingly plain, and you’ll be tempted to dress it back up. Don’t. The plainness is the feature. It means the only thing left on the page is meaning, and meaning is the only thing that ever sold anybody anything.