What is the Flesch-Kincaid Grade Level?

The Flesch-Kincaid Grade Level estimates the U.S. school grade required to understand the text. It is based on average sentence length and average syllable count per word. A score of 8 means an 8th-grader can understand the text.

What does Flesch Reading Ease measure?

Flesch Reading Ease is a 0–100 score (higher = easier). Scores above 60 are considered standard; below 30 is very difficult. It uses the same inputs as the Grade Level but weighs them differently.

Why do the formulas give different results?

Each formula weights sentence length and word complexity differently and was calibrated on a different corpus. The average grade shown is a consensus estimate across five formulas for a more robust result.

How accurate is the syllable count?

Syllable counting uses a heuristic algorithm that is accurate for most common English words but may over- or under-count irregular words. Results are estimates - use them as a guide, not a definitive measure.

Reading Level Estimator - Flesch-Kincaid, Fog, Coleman-Liau & More

Formula	Score	Notes
Flesch-Kincaid Grade	13.4	US school grade equivalent
Flesch Reading Ease	36.5	0-100, higher = easier
Gunning Fog	19.2	Years of education needed
Coleman-Liau	14.2	Based on characters, not syllables
SMOG Grade	16	Best for 30+ sentence texts
Auto. Readability (ARI)	14.3	Character and word based

Formula

Score

Notes

Flesch-Kincaid Grade

13.4

US school grade equivalent

Flesch Reading Ease

36.5

0-100, higher = easier

Gunning Fog

19.2

Years of education needed

Coleman-Liau

14.2

Based on characters, not syllables

SMOG Grade

Best for 30+ sentence texts

Auto. Readability (ARI)

14.3

Character and word based

Understanding readability formulas

Readability formulas estimate the education level required to understand a piece of text. Most formulas measure two things: sentence length (longer sentences are harder) and word complexity (measured by syllable count or character count).

Which formula should I trust?

No single formula is definitive. Each was calibrated on a different set of texts and age groups. The average grade across all five formulas is a more robust estimate than any individual score. For medical writing, SMOG is preferred. For general web content, Flesch-Kincaid and Flesch Reading Ease are most widely cited.

Target reading levels by content type

News articles: Grade 6–9 (most U.S. daily newspapers target grade 8).
Plain language / government: Grade 6–8 recommended.
Patient-facing medical content: Grade 6 or below for best comprehension.
Academic journals: Grade 12–16 is common and expected.
Marketing copy: Grade 6–8 maximizes broad comprehension.

How to lower your reading level

Break long sentences into two shorter ones.
Replace multi-syllable jargon with simpler synonyms where possible.
Use active voice instead of passive.
Put the main point at the start of each sentence (front-loading).

Formula comparison

Formula	Output	Best used for
Flesch Reading Ease	Score 0–100 (higher = easier)	General consumer text; journalism
Flesch-Kincaid Grade Level	US grade level (e.g., 8.5)	Educational materials, government documents
Gunning Fog Index	Years of education needed	Business writing and reports
Coleman–Liau Index	US grade level (character-based)	Computer-processed text; no syllable counting needed
SMOG Index	US grade level (polysyllables)	Health literacy materials; medical instructions

Plain language certification

In the United States, the Plain Writing Act of 2010 requires federal agencies to use plain language in all new or substantially revised public documents. The target is a Flesch-Kincaid Grade Level of 8 or lower for most public-facing government content. The plainlanguage.gov guidelines are freely available and widely used in healthcare, legal, and public sector communication.