Word Counter — Readability, Keyword Density & AI Rewrite

A word counter that also scores readability and keyword density

Type or paste anything and this online word counter updates in real time — words, characters, sentences, paragraphs, plus reading and speaking time. Whether you are a student checking an essay word count against a strict assignment word limit or a writer trimming a draft to a target length, the tally moves as you type. Two numbers set it apart from a plain character count: a Flesch-Kincaid readability grade and a live keyword density breakdown, so you can see both how hard your writing is and which words you lean on most. Counting, readability, and keyword density all run inside your browser — your text never leaves your device for those features.

The one exception is the optional AI Rewrite, which sends your text to Google Gemini to re-level it at a grade you choose. Everything else is offline-capable and private. Pair it with the Lorem Ipsum Generator for placeholder copy, or the Case Converter to reformat text before you count it.

How the Flesch-Kincaid grade is actually computed

The readability number in the stats bar is the Flesch-Kincaid Grade Level (FKGL). It is not a vibe or an AI guess — it is a fixed 1975 formula that estimates the US school grade a reader needs, and this tool runs the exact same equation live in your browser:

FKGL = 0.39 x (words / sentences)
                     + 11.8 x (syllables / words)
                     - 15.59

Only two things move the score: average sentence length (words / sentences) and average syllables per word (syllables / words). Long sentences and polysyllabic words push the grade up; short sentences and plain words pull it down. That is the whole lever — which is why breaking one sprawling sentence into two often drops the grade by a level on its own.

One honest limit: there is no dictionary behind the syllable count. The tool estimates syllables with a rule-based heuristic (strip a trailing silent e, count vowel groups), so unusual names and loanwords can be off by a syllable. Treat the grade as a reliable guide for ordinary prose, not a certified measurement. The tool maps the raw grade to a plain-language label using these bands:

Most web content aims for Grade 6–8. If yours reads higher and needs to reach a general audience, the AI Rewrite button re-levels it to a target grade you pick (3–16) while preserving every fact.

A worked example you can reproduce

Paste these two sentences and the readability score reads G8, Easy. Here is exactly why, step by step:

“Readability formulas estimate how hard text is to read. They combine sentence length and syllable count into a single grade.”

Counts:  20 words   2 sentences   34 syllables

                words / sentences  = 20 / 2  = 10.0   (avg sentence length)
                syllables / words  = 34 / 20 = 1.70   (avg syllables per word)

                FKGL = 0.39 x 10.0  =  3.90
                     + 11.8 x 1.70  = 20.06
                     - 15.59
                     =  8.37   ->  displayed as G8, "Easy"

Now shorten the first sentence to “Readability formulas measure how hard text is” and watch the grade fall — fewer syllables per word and a shorter average sentence both drag the score down. That live feedback loop is the point: you edit, the grade moves, and you stop guessing whether a rewrite actually simplified anything.

Keyword density: healthy signal vs keyword stuffing

The “Top Keywords by Density” panel shows your ten most-used meaningful words. Common stop words (the, and, is, and dozens more) and anything under three letters are filtered out, so what remains is the vocabulary that actually characterizes your text. Each row is a simple ratio:

density (%) = (times the word appears / total words) x 100

As a rough SEO guide, a primary keyword sitting around 1–2% and secondary terms around 0.5–1% is healthy — present enough to be clearly on-topic, not so heavy it reads as manipulation. When a single phrase climbs toward 5–6% or more, it starts to look like keyword stuffing: the copy repeats unnaturally, and modern search engines discount or penalize that rather than reward it.

The honest caveat: search engines do not publish a target density, and no exact percentage “ranks” a page. Density is a diagnostic for obvious over-use, not a dial to optimize. Covering related concepts and answering the reader’s question matters far more than hitting a number — use this readout to catch a keyword you have hammered too hard, then rewrite for a human.

Character and word limit cheat-sheet

The Characters box counts every character including spaces and line breaks — the same raw length social platforms measure — so it doubles as a character counter for anywhere you have a hard cap. Platforms adjust these limits from time to time, so verify anything mission-critical, but these are the commonly published ceilings:

Academic writing is measured in words rather than characters, so switch to the Words tile there: keep an eye on it to confirm your essay word count lands inside the assignment word limits your brief sets — many schools allow a ±10% margin, but always check the specific rubric before you submit.

Turning a word count into reading and speaking time

The Read Time and Speak Time tiles convert your word count into minutes using two standard rates: 200 words per minute for silent reading and 130 words per minute for speaking aloud. Speaking is slower because you pause, breathe, and enunciate — which is why a script always runs longer than it reads. The tool rounds up to whole minutes, so the figures below match what you will see:

For a five-minute conference talk, aim for roughly 650 words of script; for a two-minute video voiceover, about 260. Reading speed varies by reader and speaking pace varies by delivery, so use these as planning estimates, not stopwatch guarantees.

When the numbers mislead — and how to read them honestly

Every metric here has an edge case. Knowing them keeps you from over-trusting a single figure.

Lists and code inflate the readability grade

Sentences are detected only by ., !, and ?. A bulleted list or code block with no end punctuation reads as one enormous sentence, which spikes the average sentence length and the grade. Score continuous prose, not fragments.

Very short input is noisy

On one or two sentences, a single long word or a missing period swings the grade wildly. Feed it a paragraph or more before you trust the readability number.

CJK text under-counts words

Word counting splits on spaces, which works for English, French, Spanish, and other Latin-script languages. Chinese, Japanese, and Korean do not put spaces between words, so the word tally will be low — rely on the character count for those.

A low grade is not the same as good writing

Readability measures mechanical difficulty — sentence and word length — not clarity of thought. You can score Grade 5 and still be vague or wrong. Use it to catch needless complexity, then edit for meaning.

Frequently asked questions