Grammarly vs GPTZero vs Undetectable AI

Which one fits you in 2026? Traffic, pricing, input → output, tasks and community side by side.

Your tool
Grammarly
vs
Competitor 1
GPTZero
Competitor 2
Undetectable AI
Competitor 3
Suggested competitors for Grammarly: QuillBot88% Wordtune86% Originality.AI86% Copyleaks85% ProWritingAid84% Scribbr Plagiarism Checker83% LanguageTool82% StealthGPT82%
Compare
3 tools · best value per row highlighted
Your tool Grammarly
grammarly.com
Writing confidence that follows you everywhere
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Competitor GPTZero
gptzero.me
Used by over 10 million teachers and students across more than 100 countries, GPTZero detects AI-generated text across major language models while providing a suite of writing verification tools
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Competitor Undetectable AI
undetectable.ai
Undetectable AI bundles an AI text detector, an AI humanizer and an AI image detector into one account.
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Traffic estimated monthly website traffic
Monthly visits
49.3Mvisits/mo
11Mvisits/mo
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MoM change
▲ 10.8%
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6-month growth
-22.5%
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Global rank web
#688
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Avg. last 3 months
46.5M
11M
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Bounce rate lower is better
40%
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Pages / visit
7.8
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Visit duration
4m 41s
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Traffic sources
● Direct 85% · ● Referral 9%
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GrammarlyGPTZeroUndetectable AI
015.9M31.8M47.7M63.6MGrammarly · 58.8MGrammarly · 54.5MGrammarly · 55.9MGrammarly · 55.7MGrammarly · 63.6MGrammarly · 58.3MGrammarly · 54MGrammarly · 45.8MGrammarly · 44.5MGrammarly · 49.3MGPTZero · 11M10M100MGrammarly · 58.8MGrammarly · 54.5MGrammarly · 55.9MGrammarly · 55.7MGrammarly · 63.6MGrammarly · 58.3MGrammarly · 54MGrammarly · 45.8MGrammarly · 44.5MGrammarly · 49.3MGPTZero · 11MNov '25DecJan '26FebMarAprMayJunJulAug
Pricing
Model
Freemium
Freemium
Paid
Starting price
$12per month · free tier available
$12.99per month · free tier available
$5per month
Free tier
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Free trial
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API access
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Plans
Free FreePro Custom/moEnterprise Custom/mo
Free FreePremium $12.99/moProfessional $24.99/mo
10K words $5/mo20K words $9.50/mo35K words $15.75/mo50K words $21.25/mo+1 more
Capabilities input → output
Input
Text
DocumentsText
DocumentsImagesText
Output
Text
DataText
DataText
Skill level
Beginner-friendly
Beginner-friendly
Beginner-friendly
Categories
AI Detection & SafetyWriting & ContentAI DetectorAI Grammar Checker+4 more
AI Detection & SafetyAI DetectorAI Plagiarism Checker
AI Detection & SafetyAI DetectorAI Image DetectorHumanizer AI
Tasks what each tool can do · 1 shared · core   partial
Tasks covered
6
7
3
Detection
Grammar checking
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Plagiarism detection
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AI authorship detection
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Paraphrasing
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Writing
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Content detection
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Hallucination detection
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Image authenticity analysis
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Proofreading
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Audio detection
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Content authenticity verification
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Community on aitoolstime
Rating
no ratings yet
no ratings yet
no ratings yet
Upvotes
▲ 1
▲ 1
▲ 0
Saves
0
0
0
Reviews
0
0
0
Prompts
0
0
0
Verified listing
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Traffic figures are third-party estimates for the tool's own domain; tools sharing a domain with a bigger product are not counted. Pricing is captured from each tool's site and may lag.