The Readability Guide
Six readability formulas, what each measures, and how to improve a draft's score by 10+ points without losing voice.
Readability scores predict how hard a passage is to read. Most word processors and SEO plugins surface one number — usually Flesch–Kincaid — without explaining what it means. This guide covers the six formulas that matter, when each is appropriate, and the nine edits that move scores most.
The six formulas at a glance
| Formula | Output | Best for |
|---|---|---|
| Flesch Reading Ease | 0–100, higher = easier | General-audience writing |
| Flesch–Kincaid | US grade level | General default |
| Gunning Fog | US grade level | Business writing |
| SMOG | US grade level | Healthcare and patient education |
| ARI | US grade level | Quick character-based estimate |
| Coleman–Liau | US grade level | Mechanical text-processing |
Paste any text into the Word Counter and all six scores appear in the sidebar.
Articles in this guide
Flesch Reading Ease Explained: How to Score and Improve It
What the Flesch Reading Ease score actually measures, what a good score looks like, and three practical changes that move the needle.
Readability Grade Levels Explained: Flesch–Kincaid, Gunning Fog, SMOG and More
Six readability formulas, what each measures, why they sometimes disagree, and how to interpret the numbers your editor surfaces.
How to Improve Your Readability Score: 9 Practical Edits
Concrete, score-moving edits — what to change, what to ignore, and how to keep voice intact while raising Flesch Reading Ease by 10 points.
Jackpot Headline Templates That Boost Clicks, Readability, and Social Engagement
Related tools
- Word Counter — six readability scores live as you type
- Syllable Counter — for poetry and readability research
- The Complete Word Count Guide