Where your draft is checked
The tools send the draft to a dedicated Web Worker inside this tab. The worker applies formulas and pattern rules and returns counts and locations to the page. The editor uses those locations to show an excerpt and select the original text. Copy and download actions create their output on your device.
By default the editor keeps the draft in this tab’s browser session storage. Turn on “Keep this draft in this browser” to use longer-lived storage in the same browser. Use Clear and confirm Erase draft to remove the saved copies for that tool. Storage can be unavailable in some browser settings. Keep a separate copy of anything you need.
With analytics consent, Concise can record actions such as completing a check or opening an App Store link. Those events use fixed labels for the tool and action. Draft wording, excerpts, grades and counts are excluded from those events.
How counts become a readability score
A word is a run of letters. A contraction or a hyphenated word can stay together. Web addresses, email addresses and standalone numbers are excluded from word counts. A sentence normally ends at punctuation or a line break. The splitter accounts for common abbreviations, initials, decimals, quotation marks and links. Blank lines separate paragraphs. Clear Markdown headings and some isolated title lines count in the draft total and are left out of the body-text formula inputs.
- Flesch–Kincaid Grade Level = 0.39 × words per sentence + 11.8 × syllables per word − 15.59.
- Flesch Reading Ease = 206.835 − 1.015 × words per sentence − 84.6 × syllables per word.
Concise estimates English syllables with a spelling-based heuristic. Names, abbreviations and unusual words can be counted differently by different tools. The calculator shows the actual inputs and the raw values. The editor rounds the headline grade and keeps it in the app’s 0–20 display range. Its calculation shows the underlying value. Reading time assumes 200 words per minute. Document grades require 100 body words and at least three sentences.
These are estimates of written English. A short text can change score sharply when you split one sentence. A clear technical term can still add syllables. For a mixed-language draft, check each English passage on its own. The language warning recognises some common patterns and may miss short or mixed-language passages.
Microsoft Word readability statistics · Kincaid and colleagues’ original technical report · AHRQ guidance on readability formulas
Why a finding appears
- Hard sentences
- Concise flags sentences from 18 words and marks those with 28 or more as very hard. A well-organised long sentence can still work. Short dense sentences can escape a length check.
- Passive voice
- The rule looks for a form of be or get followed by a possible past participle, allowing short intervening modifiers. Ambiguous states such as “was closed” can appear as possible matches. “Was tired” is a common adjectival pattern. Reduced clauses such as “a map drawn yesterday” may escape the rule. A “by” phrase can also express a time or method, so treat the actor hint as a clue.
- Adverbs, intensifiers, hedges and qualifiers
- The tool uses a small set of English words and phrases, plus an ending-based adverb rule with exceptions. A hedge can express real uncertainty, and an adverb can give useful detail. Context determines whether to keep them.
- Complex words and wordy phrases
- Concise matches selected wording and known inflected forms such as “utilized” and “used.” A suggested alternative can change the meaning or tone. Read the sentence before applying it yourself.
The suite uses labelled examples for regular and irregular verbs, adjectives, modifiers, wording, counts, Unicode offsets and large inputs. The largest checked draft can contain 30,000 words within one million browser text units. Larger drafts stay visible for copying or downloading. Split them into sections for feedback.
Word lists and version
The web checker uses a Concise-authored set of words, phrases and examples. The syllable heuristic adapts code used by the Concise mobile app that originated with Titus Wormer’s MIT-licensed syllable package. This page describes checks v1.0, first documented November 5, 2026.
Inspect the browser requests
- Open Developer Tools, choose Network, and clear the list after the page has loaded.
- Paste a short original test sentence and run a check. The first check may load the worker and its rule files from this website.
- Inspect the requests, including any analytics events you consented to. The test sentence should stay in the editor, the worker and browser storage.
For a reproducible issue, share a short made-up example through Concise support.