There’s no single right answer
“Write at an 8th grade level” is the most common piece of readability advice on the internet, and it’s usually repeated without the context that makes it useful. The right target depends entirely on what you’re writing and who reads it. A number without that context is just a number.
These targets are starting points, not hard limits. Treat them as a place to aim, then adjust once you know your actual reader. Here are working targets by document type, with the reasoning behind each one.
Web copy: grade 6–8
Most readers scan a webpage rather than study it, often on a phone, often while distracted. A grade 6–8 target keeps sentences short enough to skim without losing meaning. This isn’t about the reader’s intelligence. It’s about matching the writing to how people actually read a screen: quickly, and rarely in a quiet room.
Business email: grade 7–9
Internal email benefits from the same plain approach as web copy, with a bit more room for shared context and jargon your team already knows. The goal is speed. A colleague reading your email at 9 a.m. between meetings shouldn’t need to reread a sentence to find the actual ask.
Technical documentation: grade 9–12
Documentation walks a line. It needs precise, unambiguous language, which naturally raises the grade level. It also needs to be usable under stress, often by someone troubleshooting a problem at an inconvenient hour. Aim for grade 9–12, and lean on structure, numbered steps, and headings, rather than vocabulary alone, to keep it navigable.
Patient-facing health material: grade 6–8
This is the target most often quoted and least often sourced. When we went looking for who actually recommends it, the answer was messier than the folklore. AHRQ names 4th-to-6th grade and puts the average U.S. adult at 8th or 9th. The EU’s guidance for clinical trial summaries names 6th. The NIH and the CDC name no grade at all, though both are routinely cited second-hand as the source of “6th grade”. The NIH goes further, cautioning that “readability scores and grade levels are not the be-all and end-all of plain language.”
It’s also the one target on this page we’ve measured at scale. U.S. regulation requires every registered clinical trial to describe itself in language intended for the lay public. That makes those summaries a rare case: the intended audience is written down. We scored 294,566 of them against the most generous bar above. 99.3% miss grade 8, and the median sits at grade 15.8 — university reading, for a field whose defined audience is the general public. No therapeutic area comes within four grade levels, and no year since 2000 approaches it.
Worth knowing before you treat that as impossible: one class of sponsor clears the target 12.9% of the time, against 0.2% for the largest group. The target is reachable; it mostly just isn’t reached. The full study and the raw data are published.
Legal plain language: grade 8–10
This is the one place grade level carries legal weight. Plain-language laws increasingly require consumer contracts, insurance policies, and government notices to hit a specific grade target. The audience is everyone, including people who don’t read the language fluently, or who are reading it under real stress. Here, the target isn’t a style preference. It’s closer to a legal and ethical obligation.
Fiction: no fixed target
Fiction doesn’t take a grade-level target well, and trying to hit one usually hurts the writing. Sentence rhythm, voice, and pacing matter more than any formula could measure. Great prose ranges freely from short, punchy sentences to long, winding ones, often within the same page. A children’s picture book and a literary novel both count as “fiction,” and they have almost nothing in common on a readability scale. Write for your reader and your story, not for a number.
Why “8th grade” gets misread
The advice to “write at an 8th grade level” gets repeated so often that it’s drifted from its original, narrower meaning. It didn’t mean write simple ideas, and it definitely didn’t mean write for people who can’t handle complexity. It meant: don’t force your reader to fight your sentence structure just to reach an idea they could otherwise grasp instantly.
Confusing “simple structure” with “simple content” leads writers to cut nuance they didn’t need to cut. You can explain a genuinely complicated idea in short, plain sentences. The complexity lives in the idea, not in how many clauses you stack into one sentence to express it.
A grade-level score can’t tell the difference between a simplified idea and a simply structured one. That distinction is entirely up to the writer, and it’s the one judgment call no formula can make on your behalf.
How to lower grade level without dumbing down
You can lower a grade level without losing a single idea. Four moves do most of the work.
Cut the padding, not the substance. Most long sentences carry filler alongside their real content: “due to the fact that” instead of “because,” “at this point in time” instead of “now.” Removing filler lowers the grade level and loses nothing.
Split, don’t summarize. A 40-word sentence usually contains two or three separate ideas stitched together with commas. Give each idea its own sentence instead of compressing them into fewer, denser ones. You keep every fact; you just stop asking the reader to hold three ideas open at once.
This is the move most people skip, and we have evidence for how much it costs. In 121,182 clinical trials, the same authors wrote both a lay summary and a technical protocol description. The lay summaries used fewer passive constructions and fewer nominalizations, so the writers were clearly trying. They still scored harder to read, and 86.8% of that gap was sentence length alone. Summarizing had pushed purpose, population, and outcome into single long sentences. Plain words, arranged into unreadable rhythm.
Replace nominalizations with verbs. “Conduct an evaluation” becomes “evaluate.” “Make a decision” becomes “decide.” These swaps shorten sentences and usually clarify who’s doing what, which a grade-level score rewards as a side effect, not the actual goal. Our nominalizations guide covers this pattern with a full conversion table.
Keep your precise words. Don’t replace an exact technical term with a vaguer one just to shave a syllable. “Anticoagulant” is the correct word in a medical context, and swapping in a fuzzier synonym trades away accuracy for a marginally better score. Simplify the sentence around the precise word instead of replacing it.
Check where you actually land
Guessing your grade level from the page is unreliable. Run your draft through the readability explainer to see your actual Flesch-Kincaid Grade Level, alongside the specific sentences pulling your score in either direction. For the full story behind the grade-level number itself, read our guide to Flesch-Kincaid Grade Level.