Writing for Sixth-Grade vs Eighth-Grade Reading Level
What actually separates a grade 6 score from a grade 8 score, shown with the formula and the same notice scored at both levels.
"Write at a sixth-grade level" and "write at an eighth-grade level" sound like very different instructions. On a readability formula, the gap between them is small and easy to see.
Scores below come from this site's calculator, run on 9 October 2026.
What two grades means in the formula
The Flesch-Kincaid Grade Level is:
Grade = 0.39 × (words per sentence) + 11.8 × (syllables per word) − 15.59
From that, a two-grade gap equals either of these:
- About five more words per sentence (0.39 × 5 = 1.95), or
- About 0.17 more syllables per word (11.8 × 0.17 = 2.0). That is roughly one extra syllable in every six words.
Most real text mixes the two.
The same notice at both levels
Grade 7.6
Your replacement card will arrive by mail within ten business days. When it arrives, activate it by calling the number printed on the sticker. You will need the final four digits of your account number to complete the activation. Your previous card will stop working once the replacement is active, so please destroy it. If your card has not arrived after two weeks, contact our customer support team and we will send another one.
74 words in 5 sentences.
Grade 5.6
Your new card will arrive by mail within ten business days. When it arrives, call the number printed on the sticker to activate it. You will need the last four digits of your account number. Your old card will stop working once the new card is active, so please destroy it. If your card has not arrived after two weeks, contact our customer support team and we will send another one.
71 words in 5 sentences.
The sentence count did not change. The edits were small:
- "replacement" became "new" (twice)
- "previous" became "old"
- "final" became "last"
- "activate it by calling the number" became "call the number ... to activate it"
- "to complete the activation" was cut
Those few swaps removed 15 syllables and moved the score by two grades.
One sentence, bigger swing
We will utilize this methodology to facilitate our investigation into market trends.
Grade 15.6.
We will use this method to help us look into market trends.
Grade 3.8.
Both sentences have 12 words. Scores for a single sentence swing widely, so treat this as a demonstration of the syllable effect, not a typical result.
What Flesch's own scale says
Rudolf Flesch's reading ease scale gives a rough check. In his table, as reproduced in William DuBay's review of readability research, a score of 60 to 70 is "Standard" and maps to 8th and 9th grade. A score of 80 to 90 maps to 6th grade.
The two notices above score 67.2 and 80.4 on that scale, which fits.
Which level to aim for
No US federal rule sets a reading grade. FDA guidance on consumer medication information suggests "the sixth to eighth grade reading level," and the targets most often cited for patient materials are 6th grade and 8th grade. Our healthcare readability post lists the sources.
A practical rule: aim for the lower end when your readers are the general public, stressed, or reading in a second language. Aim for the higher end when they chose to read and know the subject.
How to move a draft from 8 to 6
- Swap long words that have a plain twin. Our table of shorter substitutes is a start.
- Cut phrases that repeat the point, like "to complete the activation."
- Split any sentence over 25 words. See how to lower sentence length.
- Keep the words readers need, such as the name of a form or a medicine.
- Re-score with the same formula.
Do not over-read the number
A formula predicts difficulty. It does not measure it. Harry McLaughlin, who created the SMOG formula, reported that it predicts a passage's grade "within one and a half grades in 68 percent of cases." A 2013 review found that formulas varied by up to five grade levels on the same text.
So a draft that scores 6.4 is not meaningfully different from one that scores 6.0. Our post on why grade level isn't reading level explains what the number does and does not tell you.
How we checked
Both notices and both sentences were scored on this site's calculator. The sample text was written for this post.
Frequently asked questions
What is the difference between a 6th-grade and an 8th-grade reading level?
On the Flesch-Kincaid formula, two grades equal about five more words per sentence, or about 0.17 more syllables per word. In practice it is a handful of longer words and slightly longer sentences.
Should I write at a 6th-grade or an 8th-grade level?
It depends on your readers. No US federal rule sets a grade. FDA guidance on consumer medication information suggests a sixth to eighth grade reading level. For a broad public audience, the lower end is safer.
How accurate is a grade-level score?
Roughly a grade or two. The author of the SMOG formula reported a standard error of about 1.5 grades. A 2013 review found formulas varied by up to five grades on the same text.