Most working documents are written at a college reading level - policies, manuals, research summaries, insurance letters - and read by people who don't have the time or the background to work through them. Rewriting text to a lower reading level fixes that without dumbing anything down. This guide covers what "reading level" actually measures, how to pick a target grade, the techniques that move the needle, and how to use AI for the heavy lifting without changing what the text says.
What a reading level measures
The scale almost everyone uses is Flesch-Kincaid grade level, the one built into Microsoft Word. It estimates the US school grade a reader needs, and it's driven by just two things: average sentence length and average syllables per word. That's the whole trick. Shorter sentences and shorter words lower the grade; nothing about the ideas has to change.
| Target | Flesch-Kincaid grade | Who it suits | Typical sentence length |
|---|---|---|---|
| Plain English | About 8 to 10 | Expert but busy readers | Under 20 words |
| Grade 8 | 8 | General public, most web content | 15 to 18 words |
| Grade 5 to 6 | 5 to 6 | Public-facing instructions, safety and health text | 10 to 14 words |
| Technical | 12 and up | Specialists who need precision over speed | Whatever the precision needs |
A quick way to find your starting point is a readability checker: most professional writing lands between grade 11 and 14.
The techniques that actually lower the grade
- Split long sentences. Anything over 20 words is a candidate. Look for "which", "and", semicolons and dashes: each is usually a place to end one sentence and start another.
- Swap long words for everyday ones. "Utilise" becomes "use", "prior to" becomes "before", "in the event that" becomes "if". Syllable count is half the score.
- Use active voice. "The form must be submitted by the applicant" becomes "You must submit the form." Shorter, clearer, and it names who does what.
- One idea per sentence. If a sentence has two conditions and an exception, it's three sentences.
- Keep the technical terms that matter, and define them. Replacing "deductible" with "the amount you pay first" is a definition, not a swap. Keep the word and explain it once.
- Front-load the point. Say what the reader must do or know first, then the reason.
The same paragraph at three levels
Original (grade 14): "Applicants are advised that reimbursement of eligible expenses is contingent upon the submission of itemised receipts within thirty days of the date of purchase, and that failure to comply with this requirement will result in the forfeiture of the reimbursement entitlement."
Plain English (grade 9): "You can claim eligible expenses back, but only if you submit itemised receipts within 30 days of purchase. Claims made after that will not be paid."
Grade 5: "We will pay you back for approved costs. To get paid, send us the itemised receipts within 30 days of buying the item. If you send them later, we cannot pay you back."
Notice what didn't change: the 30-day rule, the receipts requirement, and the consequence. Every rewrite keeps all three. That's the test.
Using AI to do the rewriting
Rewriting by hand is slow at scale, and this is a task AI does well because the constraints are clear: shorter sentences, simpler words, same facts. Sidenote's free grade level rewriter takes any pasted text and a target - Simplify (plain English), Grade 8, Grade 5, or More concise - and rewrites it at that level without adding or dropping facts. No sign-up, and the counter shows your free rewrites for the day.
Three habits make AI rewrites safe to use:
- Give it the audience, not just the grade. "Grade 5, for patients reading a discharge letter" produces better word choices than a grade alone.
- Rewrite in sections. A page at a time keeps the meaning check manageable.
- Check the output against the source. Read the rewrite next to the original and confirm every condition and figure is still there. This is the step people skip, and it's the one that matters.
For whole documents rather than pasted text, the Explain feature in the Sidenote extension does the same job on the page you're reading, with a citation back to the original passage for each simplified point, so the meaning check is a click rather than a re-read. It's the same approach we recommend for understanding academic papers.
When not to lower the reading level
Some text carries its complexity for a reason. Contract clauses, regulatory wording and clinical criteria are precise because a looser phrasing would mean something different. For those, keep the original as the authoritative version and add a plain-English summary beside it, clearly labelled as a summary. Simplification is a layer on top of precise text, not a replacement for it.