What is WCAG 3.1.5 Reading Level?

WCAG Success Criterion 3.1.5 (Level AAA) requires that when content requires reading ability more advanced than a lower secondary education level, a supplemental version written at that lower level is provided. Lower secondary education is roughly equivalent to Grade 6–9 in the US system.

Which readability score should I use?

All three formulas are useful together. Flesch-Kincaid Grade Level is the most widely cited in US education. Gunning Fog is popular in journalism and business writing. SMOG is commonly used for healthcare materials. If all three pass, your content is very likely compliant.

What grade level do I need to target for WCAG 3.1.5 AAA?

WCAG guidance maps "lower secondary education" to roughly US Grade 6–9 (ages 11–15). This tool uses Grade 9 as the pass threshold, which is a practical and commonly accepted interpretation. Aim for Grade 6–8 for maximum accessibility.

How does the tool count syllables?

The tool uses a heuristic syllable counter based on vowel groups and common English patterns. It is accurate for most standard English text but may slightly miscount technical jargon, proper nouns, or non-English words.

What counts as a complex word in Gunning Fog?

Gunning Fog counts words with three or more syllables as complex, excluding proper nouns, compound words formed from simple words (e.g., "bookkeeper"), and common suffixes like "-ed" and "-es" that add a syllable.

Can I rely on this tool for a formal WCAG audit?

This tool provides objective readability metrics to guide your writing. A formal WCAG 3.1.5 audit may also involve human review of context, purpose, and whether a supplemental simplified version is available. Use these scores as a strong signal, not the sole determination.

Reading Level Accessibility Checker

Name: Reading Level Accessibility Checker
Availability: InStock
Author: Nham Vu

Paste any text to instantly get Flesch-Kincaid, Gunning Fog, and SMOG readability scores and see whether your content meets WCAG 3.1.5 (Reading Level AAA).

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Paste text on the left to see readability scores

Flesch-Kincaid

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Grade Level

Gunning Fog

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Fog Index

SMOG Index

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Grade Level

Text Statistics

Sentences

Words

Syllables

Complex Words

Avg Words/Sent.

Avg Syll./Word

WCAG 3.1.5 Grade Reference

Grade ≤ 9 — Meets WCAG 3.1.5 AAA (lower secondary education)

Grade 10–12 — Borderline; simplification recommended

Grade > 12 — Does not meet WCAG 3.1.5 AAA

Summary

Paste any text to instantly get Flesch-Kincaid, Gunning Fog, and SMOG readability scores and see whether your content meets WCAG 3.1.5 (Reading Level AAA).

How it works

Paste or type your text into the input panel on the left.
The tool counts sentences, words, and syllables in real time.
Flesch-Kincaid Grade Level, Gunning Fog Index, and SMOG Index are calculated using standard formulas.
Each score is compared against the WCAG 3.1.5 AAA threshold (roughly Grade 9 or below).
A pass/fail badge appears for each metric so you know exactly which areas need simplification.
Detailed stats (sentence count, word count, average sentence length, complex word count) are shown below the scores.

Use cases

Audit government and public-sector websites for plain-language compliance.
Check healthcare or legal copy before publishing to ensure patients or clients can understand it.
Verify instructional content meets WCAG 3.1.5 AAA before an accessibility audit.
Benchmark e-learning course text against grade-level targets.
Simplify marketing copy to improve comprehension for broader audiences.
Evaluate terms and conditions or privacy policies for readability.
Review news articles or blog posts for accessible language.
Support UX writers and content strategists with objective readability data.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu