A plagiarism detector compares your text against web pages, academic sources and private databases to flag copied or closely paraphrased passages, so you publish original work and protect your rankings, credibility and brand trust. Modern tools also score similarity and detect AI-generated text. The seven tools below cover quick free checks, writing assistants, academic-grade scans and enterprise APIs, with current prices for each.
Why Plagiarism Detector Tools Matter
An originality check before you publish protects your search performance, your academic standing and the trust readers place in your brand. Content now gets produced faster than ever, often with AI help. Without a check, duplicate or unoriginal passages slip through. A detector analyses your text against large datasets, highlights matches with their sources and builds originality checks into your normal content production workflow.
What does a plagiarism detector give your team?
A plagiarism detector gives your team a similarity score, the matching sources and a repeatable check you run on every piece before it goes live. The main benefits:
- Finds copied or duplicated content.
- Detects paraphrased or rewritten passages.
- Shows similarity scores and source references.
- Flags text likely to be AI-generated, on tools that support it.
- Reduces risk in SEO and publishing.
- Scales originality checks across a content team.
1. PlagiarismDetector.net
PlagiarismDetector.net suits students, freelancers and small teams that want a quick, low-cost web plagiarism check.
PlagiarismDetector.net scans your text against online sources and highlights matched passages with a link to each source. People use it to check essays, articles and web pages before they submit or publish. It detects exact and near-exact copying from public websites well, which makes it a dependable copy-and-paste check rather than a deep academic scan.
Core features:
- Web-based plagiarism checking
- Text, document and URL upload
- Matched text highlighted with source links
- Free and paid plans
- Multilingual detection
PlagiarismDetector.net pricing and suitability
PlagiarismDetector.net pairs a limited free version with paid monthly plans priced by word count, and yearly billing takes 10% off. Prices are shown in $ with no currency code.
| Plan | Monthly price | Yearly billing | Words a month | Includes |
|---|---|---|---|---|
| Free | $0 | Not applicable | Limited | Basic scanning |
| Basic | $19.99 | $17.99 a month | 72,000 | Web plagiarism checks |
| Premium | $39.99 | $35.99 a month | From 144,000 | API access, 1 user seat |
Source: PlagiarismDetector.net pricing, checked October 2026. Team plans with more seats and custom pricing are also listed.
2. Grammarly Plagiarism Checker
Grammarly suits writers and teams that want plagiarism checks built into the writing assistant they already use.
Grammarly combines grammar, clarity and originality checks in one tool, so you catch accidental plagiarism while you edit. Its database is not as deep as specialist academic checkers; its strength is ease of use inside everyday writing.
Core features:
- Plagiarism detection across web sources
- Grammar and writing suggestions
- AI-generated text detection
- Citation suggestions
- Real-time feedback
Grammarly pricing and suitability
Grammarly includes its plagiarism checker only in the paid Pro and Enterprise plans; the Free plan has no plagiarism detection. It works as a bundled feature rather than a dedicated detection platform.
| Plan | Price | Billing | Suitable for | Plagiarism checker |
|---|---|---|---|---|
| Free | USD 0 a month | Free | Basic writing | Not included |
| Pro | USD 12 per member a month | Billed annually (USD 144 a year); also USD 60 a quarter or USD 30 monthly | Students and writers | Included |
| Enterprise | Quote-based | Contact sales | Teams and organisations | Included |
Sources: Grammarly plans, checked October 2026; quarterly and monthly rates from Grammarly Support.
3. QuillBot Plagiarism Checker
QuillBot suits students and writers who want to find and fix plagiarism in the same tool.
QuillBot combines plagiarism detection with paraphrasing and rewriting tools. Writers who work with rewritten or AI-assisted drafts use it most. Its detection covers general use well, though not to the depth of academic-focused checkers.
Core features:
- Plagiarism detection
- Paraphrasing tool
- AI writing support
- Citation generator
- Multiple writing modes
QuillBot pricing and suitability
QuillBot puts its plagiarism checker in the Premium subscription, with a monthly word allowance.
| Plan | Price | Billing | Suitable for | Plagiarism allowance |
|---|---|---|---|---|
| Free | USD 0 a month | Free | Light use | None listed |
| Premium | USD 8.33 a month | Billed annually | Students and writers | 25,000 words a month |
Source: QuillBot Premium, checked October 2026.
4. Scribbr Plagiarism Checker
Scribbr suits students and researchers who need an academic-grade check on a single important document.
Scribbr checks documents against 99.3 billion current and historical web pages and 8 million publications from more than 1,700 publishers, including Springer, IEEE, Elsevier, Wiley-Blackwell and Taylor and Francis. A 2018 Turnitin partner story states that Scribbr includes Turnitin technology in its platform, and Scribbr's own checker page describes its software as similar to the software most universities and publishers use. That makes it strong at detecting paraphrased academic text.
Core features:
- Academic publication database
- Detection technology similar to university software
- Detailed similarity reports
- Source comparison
- Citation support
Scribbr pricing and suitability
Scribbr charges a one-time price per check by document length, not a subscription, which suits occasional but high-stakes checks.
| Document length | Price | Billing | Suitable for | Limitations |
|---|---|---|---|---|
| Up to 7,499 words | USD 19.95 | Per check | Essays | Costly for frequent use |
| 7,500 to 49,999 words | USD 29.95 | Per check | Research papers | No subscription option |
| 50,000 words and above | USD 39.95 | Per check | Theses and long documents | No subscription option |
Source: Scribbr plagiarism checker, checked October 2026.
5. Turnitin
Turnitin suits universities and institutions that need plagiarism checks built into teaching and submission systems.
Turnitin is widely used by universities and institutions worldwide. Its database includes academic journals, student submissions and proprietary content, and it integrates with learning management systems. It sells to institutions rather than individuals.
Core features:
- Academic database access
- Similarity reports
- Institutional integration
- Learning management system compatibility
- Detailed content analysis
Turnitin pricing and suitability
Turnitin pricing is quote-based and available only through an institutional licence; it sells no individual licences or single-use subscriptions. Independent users are pointed to iThenticate credits instead.
| Plan | Price | Billing | Suitable for | Limitations |
|---|---|---|---|---|
| Institutional licence | Custom quote | Institutional contract | Universities and schools | Not available to individuals |
Source: Turnitin help article on individual licences, checked October 2026.
6. GPTZero
GPTZero suits educators and content reviewers whose main question is whether a text was written by AI.
GPTZero focuses on AI detection and adds plagiarism checks alongside it. It scores text sentence by sentence and reports the probability of AI authorship. Accuracy varies with the complexity of the content, so treat its scores as evidence to review, not a verdict.
Core features:
- AI detection
- Plagiarism detection
- Sentence-level analysis
- Probability scoring
- Reporting tools
GPTZero pricing and suitability
GPTZero offers a free sign-up and paid plans priced by usage, including a Professional Team plan billed per seat with 500,000 words per member a month. See GPTZero pricing for current plans, checked October 2026.
7. Copyleaks
Copyleaks suits businesses and institutions that need plagiarism and AI detection at scale, with API and learning management system integrations.
Copyleaks checks text against web and proprietary databases and reports AI and plagiarism findings together. Organisations that verify content in volume use its API.
Core features:
- Plagiarism detection
- AI content detection
- API integration
- Multi-language support
- Learning management system integration
Copyleaks pricing and suitability
Copyleaks prices by unified credits that cover words or images, with AI and plagiarism detection in one report, which scales well but makes costs harder to estimate up front. Prices are shown in $ with no currency code.
| Plan | Annual billing | Monthly billing | Allowance | Suitable for |
|---|---|---|---|---|
| Personal | $13.99 a month ($167.88 a year) | $16.99 a month | Annual: 1,200 credits, up to 300,000 words; monthly: 100 credits, up to 25,000 words | Individuals |
| Pro | $74.99 a month ($899.88 a year) | $99.99 a month | Annual: 12,000 credits, up to 3,000,000 words; monthly: 1,000 credits, up to 250,000 words | Small teams and heavy users |
| Enterprise | Quote-based | Quote-based | Custom | Large organisations |
| Education | Quote-based | Quote-based | Custom | Schools and universities |
Source: Copyleaks pricing, checked October 2026.
How to Choose the Right Plagiarism Detector Tool
Choose by how you use content and how much accuracy the decision needs: academic submissions need a deep database, while web content needs fast, repeatable checks. A student checking a thesis needs a different tool from an SEO team checking twenty blog posts a week.
Which plagiarism detector fits which use?
Match the tool to your main task: quick checks, everyday writing, rewriting, academic work, institutions, AI detection or enterprise scale.
| Tool | Best for | Strengths | Limitations | Pricing model |
|---|---|---|---|---|
| PlagiarismDetector.net | Quick checks and free use | Free access, easy to use | Limited database | Monthly by words |
| Grammarly | General writing | Built into the writing assistant | Limited database | Bundled in Pro |
| QuillBot | Rewriting workflows | Detection and paraphrasing together | Less depth than academic tools | Premium subscription |
| Scribbr | Academic use | Large academic database | Costly per check | Per document |
| Turnitin | Institutions | Deep academic database | No individual access | Institutional licence |
| GPTZero | AI detection | AI-focused scoring | Accuracy varies | By usage and seats |
| Copyleaks | Enterprise | Scalable, API | Credit pricing harder to estimate | Unified credits |
Make Originality Part of Your Content Process
An originality check protects rankings and trust only when it runs on every piece, so build it into your publishing workflow, not just your final review. Each tool above serves a different purpose, from academic verification to AI detection and enterprise workflows. Read the content marketing guide, find duplicate pages with the on-page SEO audit, and monitor the results with rank tracking tools.