ProseScore vs Readable.io

Readable.io charges $8/month for readability analysis. ProseScore gives you 8 formulas, sentiment analysis, keyword extraction, and SEO scoring — free, with no signup, running entirely in your browser.

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Side-by-side comparison

Feature	ProseScore	Readable.io
Price	Free tier / Pro $3.99/mo or $19.99 lifetime	$8/mo (ContentPro plan)
Signup required	No — paste and go	Yes — account required
Privacy	100% client-side	Cloud-based (text sent to servers)
Readability formulas	8 formulas + consensus grade	10+ formulas (Linsear Write, Fry Graph, etc.)
Sentiment analysis	✓	—
Keyword extraction	✓	—
SEO scoring	✓	—
Open source	✓ MIT license	—
Works offline	✓	—
Usage limits (free)	No limits	Limited free trial
Team collaboration	—	✓
API access	—	✓
Email / URL scanning	—	✓

Shared readability formulas

Both ProseScore and Readable.io support the core readability algorithms. ProseScore averages all eight into a single consensus grade. Readable offers additional niche formulas like Linsear Write and the Fry Graph.

Flesch-Kincaid Grade Level

The most widely used readability formula. Maps text to a U.S. school grade level based on sentence length and syllable count.

Gunning Fog Index

Estimates the years of formal education needed. Penalizes complex (3+ syllable) words more heavily than Flesch-Kincaid.

Coleman-Liau Index

Uses character count instead of syllables, making it more reliable for technical text with acronyms and abbreviations.

SMOG Index

Considered the gold standard for health literacy. Counts polysyllabic words to estimate reading difficulty.

Automated Readability Index

Character-based formula designed for automated assessment. Fast and effective for large documents.

Dale-Chall Readability

Compares words against a list of 3,000 familiar words. Particularly accurate for lower reading levels.

Why writers choose ProseScore over Readable

No subscription, no signup Readable requires an account and charges $8/month for its ContentPro plan. ProseScore works the moment you open the page — no email, no credit card, no trial expiration.

Your text never leaves your device Readable is cloud-based: your text is sent to their servers for analysis. ProseScore runs entirely in your browser. Nothing is transmitted, stored, or logged.

No limits on the free tier Readable's free trial restricts what you can analyze. ProseScore's free tier has no word limits and no daily caps. Upgrade to Pro for additional formulas and features when you're ready.

Open source and transparent Built on textlens, an MIT-licensed TypeScript library. Inspect the algorithms, contribute improvements, or integrate into your own tools.

When Readable might be the right choice

You need team features Readable offers team collaboration, shared reports, and multi-user accounts. ProseScore is designed for individual writers.

You need an API Readable provides a REST API for programmatic access. If you need to integrate readability scoring into your pipeline, Readable's API or ProseScore's underlying textlens npm package are both options.

You need email or URL scanning Readable can scan live URLs and email campaigns. ProseScore works with pasted text only.

Try ProseScore free

No account, no email, no credit card. Paste your text and get results instantly.

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Pro from $3.99/mo or $19.99 lifetime — all 8 formulas, sentiment, SEO scoring, export