ProseScore vs Grammarly

Grammarly Premium costs $144/year and sends every word you type to their servers. ProseScore gives you 8 readability formulas, keyword extraction, and SEO scoring — free, private, and entirely in your browser.

Try ProseScore free →

No sign-up required. No data leaves your browser.

Side-by-side comparison

Feature	ProseScore	Grammarly
Price	Free forever	Free (limited) / Premium $12/mo ($144/yr)
Privacy	Client-side only — zero data sent	All text sent to Grammarly cloud
Readability formulas	8 formulas + consensus grade	1 proprietary score
Open source	✓ MIT license	—
Account required	No account needed	Sign-up required
Tracking / cookies	Zero tracking	Extensive data collection
Keyword extraction	✓ with density analysis	—
SEO scoring	✓	—
Instant results	✓ no cloud round-trip	Depends on server response
Grammar & spelling	—	✓
Writing style suggestions	—	✓ + tone detection
Plagiarism checker	—	Premium only
Browser extension	—	✓ + desktop app
AI writing assistant	—	✓

8 readability formulas in one tool

Grammarly uses a single proprietary readability score. ProseScore runs all eight major readability algorithms and averages them into a consensus grade for a more accurate, well-rounded assessment.

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.

Spache Readability

Designed specifically for primary-grade text (grades 1–3). Uses a familiar word list tuned for early readers.

Flesch Reading Ease

Scores text on a 0–100 scale (higher = easier). The most intuitive readability metric for non-technical users.

Why writers choose ProseScore for readability

Free forever, not freemium Grammarly gates readability behind its Premium plan at $12/month. ProseScore gives you all 8 readability formulas, keyword extraction, and SEO scoring at no cost.

Your text never leaves your device Grammarly processes your text on their servers and collects usage data. ProseScore runs entirely client-side. No servers, no API calls, no data collection. Your drafts stay private.

8 formulas beat 1 proprietary score A single score can mislead. ProseScore runs eight proven readability algorithms and averages them into a consensus grade you can trust.

SEO and keyword analysis built in ProseScore extracts keywords with density percentages and generates an SEO score. Grammarly doesn't offer keyword extraction or SEO analysis at any tier.

No account, no tracking, no cookies Open the page, paste your text, get results. No email, no sign-up form, no tracking scripts watching what you write.

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

When Grammarly is the better choice

ProseScore and Grammarly solve different problems. If you need grammar correction, spelling fixes, tone detection, or an AI writing assistant, Grammarly is the right tool. ProseScore focuses on readability analysis, keyword extraction, and SEO scoring — and does it for free, privately, in your browser.

Also compare

ProseScore vs Hemingway App ProseScore vs Readable.io

Try ProseScore free

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

Open ProseScore →

Free forever — 8 readability formulas, sentiment, keyword extraction, SEO scoring