Text tools
Reading Level Calculator
Analyze text readability with Flesch-Kincaid, Gunning Fog, SMOG, ARI, and Coleman-Liau scores locally in your browser.
Paste text to analyze its readability with multiple standard formulas. Calculations run locally in your browser; your text is not uploaded or stored.
This tool estimates readability using standard formulas. Syllable counting is heuristic and may not match dictionary counts exactly. Results are estimates, not definitive assessments. For professional editing, consult a human editor.
Check how easy your text is to read.
Paste text to see word count, sentence count, syllable count, and six standard readability formulas. Flesch Reading Ease rates 0–100 (higher is easier). Flesch-Kincaid, Gunning Fog, SMOG, ARI, and Coleman-Liau estimate the US grade level needed to understand the text. Syllable counting uses a heuristic algorithm; results are estimates. All analysis runs locally in your browser, so your text is not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What readability formulas does this calculator use?
The calculator computes six standard formulas: Flesch Reading Ease (0–100, higher is easier), Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index, Automated Readability Index (ARI), and Coleman-Liau Index. The grade-level formulas estimate the US school grade needed to understand the text.
How does Flesch Reading Ease differ from the grade-level formulas?
Flesch Reading Ease scores 0–100, where higher means easier to read (e.g., 90+ is very easy, 30–50 is difficult). The other formulas output a US grade level (e.g., 8 means 8th grade). Both types are shown so you can choose the metric that fits your audience.
How are syllables counted?
Syllables are estimated with a heuristic algorithm that counts vowel groups, adjusts for silent e, and handles common -le endings. This is an approximation; dictionary syllable counts may differ, so treat results as estimates rather than definitive measurements.
What text length works best?
All formulas work with any text, but grade-level estimates are most reliable for passages of 100+ words. SMOG specifically requires at least 3 sentences to produce a valid result; fewer sentences will show N/A for SMOG.
Is my text private?
Yes. All counting, formula calculations, and copying happen locally in your browser. CodeASystem does not upload or store the text you paste.