Best GPTZero Alternatives for Plagiarism Checking
13 AI tools that can replace GPTZero for checking for plagiarism, ranked by how closely they match. The percentage is a match score, not a popularity score.
Replacing: GPTZero — Used by over 10 million teachers and students across more than 100 countries, GPTZero deteInput: text, documents · Output: text, data
1
Developers get API access for building AI detection into their own apps
Developer-friendly detector with API access for embedding in your own apps; plagiarism checks too
Input: text, documents, web pages · Output: text, data
Free planFrom $12.95/mo
82%Strong alternative · same core category as GPTZero
00
How the score adds up
Score set by our editors after reviewing both products; the overlap below is what they weighed.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
2
Copyleaks is a content authenticity platform that checks whether text was written by AI and whether it copies existing sources.
Content authenticity platform checking AI authorship and copied text, plus image detection and API
Input: text, images, video, documents, code · Output: data
From $13.99/moAPI
80%Strong alternative · same core category as GPTZero
00
How the score adds up
Score set by our editors after reviewing both products; the overlap below is what they weighed.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Fake Image Detection
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
3
Turnitin is an academic integrity suite that schools, universities, and research organizations use to verify originality and deal with AI-written text.
Academic integrity suite for schools and universities, with LMS integration and team features
Input: text, documents · Output: data
Teams
72%Partial replacement — covers the main need with gaps
00
How the score adds up
Score set by our editors after reviewing both products; the overlap below is what they weighed.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
4
Writing confidence that follows you everywhere
Input: text · Output: text
Free planFrom $12/mo
70%Partial replacement — covers the main need with gaps
00
How the score adds up
Score set by our editors after reviewing both products; the overlap below is what they weighed.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Grammar CheckingRewritingWritingHumanizing Text
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
5
Rephrase until it sounds right
Input: text, images, documents · Output: text, images, documents, slides
Free planFrom $19.95/mo
66%Partial replacement — covers the main need with gaps
00
How the score adds up
Score set by our editors after reviewing both products; the overlap below is what they weighed.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Grammar CheckingRewritingSummarizingWritingHumanizing Text
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
6
ZeroGPT processes text quickly to detect AI-generated content
Quick text scans for AI-written content, with humanizer and plagiarism tools; from $7.99
Input: text, images, video, documents · Output: text
From $7.99/mo
60%Partial replacement — covers the main need with gaps · same core category as GPTZero
00
How the score adds up
Score set by our editors after reviewing both products; the overlap below is what they weighed.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Fake Image DetectionHumanizing Text
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
7
Trinka is an AI writing assistant and grammar checker aimed at academic and technical writing.
Input: text, documents · Output: text, documents
Free planTeams
59%Limited overlap
00
How the score adds up
- Offers Plagiarism Checking as a secondary capability42/70
- Shares GPTZero's other goals8/10
- Feature description similarity9/20
Capped below the editor-ranked picks above it.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Grammar CheckingRewritingWriting
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
8
Winston AI is an AI content detector and plagiarism checker built for education, SEO, and writing.
Built for education, SEO and writing; detector plus plagiarism checker with team features and API
Input: text, images, documents · Output: data
Free planFrom $10/moAPITeams
59%Limited overlap · same core category as GPTZero
00
How the score adds up
- Offers Plagiarism Checking as a secondary capability42/70
- Shares GPTZero's other goals10/10
- Feature description similarity13/20
Capped below the editor-ranked picks above it.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Fake Image Detection
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
9
Scribbr Plagiarism Checker compares a document with a database of 99 billion web pages and 8 million publications and shows where the text matches existing sources.
Input: text, documents · Output: documents
Free plan
59%Limited overlap
00
How the score adds up
- Built for Plagiarism Checking (its core category)70/70
- Shares GPTZero's other goals8/10
- Feature description similarity6/20
Capped below the editor-ranked picks above it.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Grammar Checking
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
10
Pangram Labs makes an AI detector that checks whether text was written by a person or generated by a language model.
Input: text, images, documents · Output: data
Free planFrom $20/moAPIBrowser extension
59%Limited overlap · same core category as GPTZero
00
How the score adds up
- Offers Plagiarism Checking as a secondary capability42/70
- Shares GPTZero's other goals10/10
- Feature description similarity13/20
Capped below the editor-ranked picks above it.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Fake Image Detection
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
11
Phrasly is an AI writing workspace built around a humanizer that rewrites machine-generated text so it reads like natural human writing, without watermarks.
Input: text · Output: text
Free trialFrom $9.8/mo
58%Limited overlap
00
How the score adds up
- Offers Plagiarism Checking as a secondary capability42/70
- Shares GPTZero's other goals8/10
- Feature description similarity9/20
Capped below the editor-ranked picks above it.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Humanizing Text
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
12
Smodin is an AI writing toolkit that puts an AI content detector, an AI humanizer, a plagiarism checker, an AI writer, a rewriter and an AI chat assistant in one account.
Input: text, documents · Output: text, data
57%Limited overlap
00
How the score adds up
- Offers Plagiarism Checking as a secondary capability42/70
- Shares GPTZero's other goals8/10
- Feature description similarity7/20
Capped below the editor-ranked picks above it.
Shared goals 2 of the 2 we tag GPTZero for
AI DetectionPlagiarism Checking
Also tagged for
Grammar CheckingRewritingWritingHumanizing Text
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
13
Yomu AI is an academic writing assistant that drafts, edits and cites essays, research papers, literature reviews and theses inside one document editor.
Input: text, images, documents · Output: text
From $10/mo
52%Limited overlap
00
How the score adds up
- Offers Plagiarism Checking as a secondary capability42/70
- Shares GPTZero's other goals4/10
- Feature description similarity6/20
Capped below the editor-ranked picks above it.
Shared goals 1 of the 2 we tag GPTZero for
Plagiarism Checking
Also tagged for
Essay WritingPDF WorkResearch Papers
Goal tags are curated and capped, not a full feature audit — a missing tag is not a missing feature.
Can it really replace GPTZero for checking for plagiarism? Vote on each alternative — no account needed. Votes gently reorder the list; they never change the match score.
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At a glance: top GPTZero alternatives for Plagiarism Checking
| Tool | Match | Input | Output | Pricing | Free plan | Rating | Category |
|---|---|---|---|---|---|---|---|
| Originality.AI | 82% | text, documents, web pages | text, data | From $12.95/mo | Yes | — | AI Detector |
| Copyleaks | 80% | text, images, video, documents, code | data | From $13.99/mo | No | — | AI Detector |
| Turnitin | 72% | text, documents | data | — | No | — | AI Plagiarism Checker |
| Grammarly | 70% | text | text | From $12/mo | Yes | — | AI Grammar Checker |
| QuillBot | 66% | text, images, documents | text, images, documents, slides | From $19.95/mo | Yes | — | AI Rewriter |
| ZeroGPT | 60% | text, images, video, documents | text | From $7.99/mo | No | — | AI Detector |
Frequently asked
What is the best GPTZero alternative for checking for plagiarism?
Originality.AI (82% match) is the closest alternative to GPTZero for checking for plagiarism. Copyleaks (80% match) and Turnitin (72% match) come next.
Is there a free alternative to GPTZero for checking for plagiarism?
Yes. 7 of the 13 ranked alternatives have a free plan or free tier, including Originality.AI, Grammarly, QuillBot.
How is the match percentage calculated?
It measures how much of GPTZero's job a tool can take over for checking for plagiarism: shared core category, how many of the same use cases it covers and how similar its feature set is. Popularity and ratings never change the percentage; they only break ties in the order. Lists are recomputed nightly and reviewed by editors for the most-visited tools.
How this list is ranked
The match score measures how much of GPTZero's job each tool can take over when the goal is checking for plagiarism: shared core category, how many of the same use cases it covers, and how similar its feature set is. Popularity and ratings do not change the score; they only break ties in the order.
Lists are recomputed nightly from the live catalog and reviewed by our editors for the most-visited tools. Sponsored placements are marked and sit outside the ranking.