L
LGrammar, spelling and style checker for 30+ languages, with AI rephrasing
Free, from $5.83/mo
Grammarly vs StealthGPT
Pricing, features, platforms and who each one suits — side by side.
G
Choose Grammarly if…
- you want a free plan to start with
- you work on Windows, macOS, Android
- you're in its core audience: students, professionals
S
Choose StealthGPT if…
- you need an API to build on
- you're in its core audience: students, content writers
Side by side
Feature Grammarly StealthGPT
Pricing modelFreemiumFree trial
Starting price—$29.99/mo
Free plan
Free trial
API
Open source
Trains AI on your contentYes, unless you opt out—
Data retentionSaved documents kept until you delete them or your account—
Security and complianceSOC 2 Type II—
AI rewrites—
Plagiarism checker—
AI text detection—
Non-English checking—
Word/Google Docs add-in—
Browser extension—
Custom style guide—
PlatformsWeb, Chrome, Windows, macOS, iOS, AndroidWeb, iOS, Chrome, API
CategoryGrammar & ProofreadingAI Humanizers
CompanySuperhuman Platform Inc. · United States · since 2009 · part of SuperhumanXYZ AI, Inc.
Full feature lists
G Grammarly
- Grammar, spelling and clarity checks
- Full-sentence and paragraph rewrites
- Tone suggestions and adjustment
- AI Detector and Humanizer agents
- Plagiarism checker and citation generator
- Browser extensions for Chrome, Safari, Firefox and Edge
- Microsoft Office and Google Docs integrations
- Brand tone and style guides for teams
S StealthGPT
- AI Humanizer with Lite and Super rewrite modes
- AI Detector with instant AI-likelihood score
- Stealth Writer essay generator with citations
- Stealth Agent for research, drafting and fact-checking
- Chat with PDF and photo-to-answers
- AI watermark detectors and removers
- REST API with bulk requests of up to 100 items
- WordPress, Zapier, n8n and MCP integrations
Their home pages
What each vendor shows first: the pitch, the plans and the sign-up.
Grammarly · grammarly.com
StealthGPT · stealthgpt.aiWhat you'd pay
The cheapest plan that fits, per month, billed yearly where the plan offers it.
What the free plans include
Grammarly
- Generate text with 100 AI prompts (100 prompts / month)
- 1 style guide
- 1 brand tone
- User groups: 2
StealthGPT
No free plan.
All plans and prices
Grammarly
FreeFree
ProPrice not shown on page ("Try for $0.00" trial only)
EnterpriseCustom
StealthGPT
Pro$29.99/mo ($1 for 3-day trial)
Max$49.99/mo ($1 for 3-day trial)
Enterprise$179.99/mo
Price changes we've recorded
We re-read each pricing page every month and log what changed.
Grammarly
- Nov 5, 2026Pro: USD price not shown to our fetcher (EUR only) → $0
- Nov 5, 2026Free: €0 → Free; Pro: €12/member/mo billed annually (€30 billed monthly) → USD price not shown to our fetcher (EUR only)
StealthGPT
No changes since we started tracking.
Strengths and limitations
Grammarly
- Free plan includes grammar checks and 100 AI prompts a month
- Available on desktop, mobile, browsers, Office and Google Docs
- Pro includes a free trial with a reminder email before it ends
- States it does not sell user content or let third parties train on it
- Free plan lacks tone adjustment and full-sentence rewrites
- Pro limits AI prompts to 2,000 per member per month
- No public API listed
StealthGPT
- Pro and Max can be tried for $1 for 3 days
- API, MCP, Zapier and n8n integrations available
- Available on web, iOS and as a Chrome extension
- Interface available in nine languages
- Pro plan limits each request to 1,000 words
- Team seats only on Max and Enterprise
- Trial converts to $29.99/month or more
More comparisons
Other options to consider
LL
Free, from $5.83/mo
L
Grammar, spelling and style checker for 30+ languages, with AI rephrasing
Grammar & ProofreadingFree planAPIOpen source
P
PGrammar checking, style reports and story critique for fiction writers
Free, from $10/mo
P
Free, from $10/mo
P
Grammar checking, style reports and story critique for fiction writers
Grammar & ProofreadingFree plan
G
GG
Freemium
G
AI grammar, spelling and rephrasing help for English writers on any device
Grammar & ProofreadingFree planAPI
W
WW
Free, from $4.89/mo
W
AI rewriting, summarizing and grammar assistant for everyday writers
Paraphrasing & RewritingFree plan
S
SS
Free, from $12/mo
H
HReadability editor that flags wordy, unclear writing and offers AI fixes
From $8.33/mo
H
From $8.33/mo
H
Readability editor that flags wordy, unclear writing and offers AI fixes
Grammar & Proofreading
Facts from each vendor's public pages, prices checked Nov 5, 2026. Editorial policy