A plagiarism checker compares a text with web pages, publications and sometimes stored student papers, and reports where it matches.
This guide ranks eleven products on the first ninety days of setup, the real cost once checks and credits are counted, how documents are handled, and who each suits: schools, publishers or individual writers.
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vendor. How that works.
In short
What plagiarism checkers software does
A plagiarism checker is software that compares submitted text against web pages, published works and sometimes stored papers, and reports matching passages with their sources and a similarity score.
In this order: setup effort, what it really costs, how your data comes back out, whether
you can leave, and who each plagiarism checkers tool is built for. One rule sits on top of those tests:
Places 1 to 3 go to challengers, vendors outside the best-known brands in a category, wherever the category has them; the established names follow from place 4 in their ranked order. Why those five, and why there is no
score out of ten, is on the how we work page.
Quoted per institution; contact sales, no prices on the product pages
—
Universities needing AI findings inside the same system as similarity checks and grading
Freelancers and agencies wanting a self-serve detector with a card
Country is where the vendor is headquartered or contracts from, which is a
different question from where your data is hosted. Where the two tell different stories, the
entry says so.
Pay-per-check plagiarism and AI scans, no subscription needed
Ranked #1 of 11 in Best Plagiarism Checkers in 2026.
Published pricingEurope
PlagiarismSearch is run by System Technology Online Spain SL, though the terms make System Tech Online USA Inc. the merchant of record for standard self-service payments. Submissions are bought as one-time packs or monthly and three-month packages, each counting plagiarism and AI checks.
It states that uploaded documents are not stored. Integrations are a Moodle plugin, a Google Docs add-on and an API, the last starting at the Standard monthly package. Test your own samples first.
What stands out
Pay per check
Moodle and API
Documents not stored
Where it costs you
Card payments for self-service packages are taken by a US company, so a European buyer contracts outside the EU.
The pages give no size or list for the source database, so coverage must be tested on your own documents.
Right for
Students, editors and small teams wanting single checks without any subscription
Wrong for
Universities needing a repository of earlier student work
SpainDaily allowance after registration; one-time packs and monthly packages, prices published
Single-purpose web plagiarism search billed per search, not subscription
Ranked #2 of 11 in Best Plagiarism Checkers in 2026.
Published pricingElsewhere
Copyscape is provided by Indigo Stream Technologies Ltd, which also runs Siteliner and Giga Alert. Premium charges per search, with extra for each hundred words beyond the first two hundred.
Batch Search takes up to 10,000 pages, the API allows scripts, and a private index checks new copy against your own content. Google is the search provider, so private documents and paywalled sources stay outside its reach. The terms are governed by Gibraltar law.
What stands out
Per-search billing
Batch and API
Web content only
Where it costs you
Searches run through Google, so it finds public web copies and nothing from a closed repository of student papers.
Every check costs money, so a team scanning thousands of pages should price the batch before starting.
Right for
Website owners and content managers checking pages for copies and finding scrapers
Wrong for
Schools wanting to compare essays with earlier student submissions
Not stated by the vendorPay per search, prices published; separate free comparison tool
French independent with teacher licences and student credit packs
Ranked #3 of 11 in Best Plagiarism Checkers in 2026.
Published pricingEurope
Compilatio states its corporate record plainly: a simplified joint-stock company registered in Annecy, hosted by OVH. Magister serves teachers and needs a demo, while Studium lets students create an account to check work before submitting.
The AI function sits inside a plagiarism suite and names its output as passages potentially generated by AI. Real cost is unknown until a quote arrives. A reseller programme is advertised, so partner routes exist.
What stands out
Magister for teachers
Studium credits
French company
Where it costs you
The vendor calls AI findings potential, so results need human judgement
Teacher edition has no public price, only a demo route
Right for
European schools wanting a French-hosted plagiarism and AI checker with teacher and student editions
Wrong for
Content agencies scanning large volumes of web copy
FranceStudent credit packs published; institutional licences quoted on request
Dutch student-focused checker with a fixed price per document
Ranked #4 of 11 in Best Plagiarism Checkers in 2026.
Published pricingEurope
Scribbr starts easily: no account is needed for the free English check, and premium begins at a listed starting price. Premium adds Dutch, English and German detection, but each check stays capped at 500 words on the page we read.
Independence is limited, since Learneo, Inc. owns and operates the service and the plagiarism check is run by Turnitin. Exit and data export terms sit in the security and privacy pages, which we did not review in full.
What stands out
Per-document price
Free partial scan
Self-plagiarism upload
Where it costs you
Free checks cover English only and a maximum of 500 words each
Dutch detection requires buying the premium plagiarism check first
Right for
Dutch and Flemish students checking a thesis who want detection bundled with plagiarism
Wrong for
Teams scanning long web articles or wanting an API
NetherlandsPrice per document by word count, published; free check shows top sources only
Word-allowance checker with a free tier and AI detector bundled
Ranked #5 of 11 in Best Plagiarism Checkers in 2026.
Free tierPublished pricingElsewhere
Quetext Software LLC offers a free tier at 1,000 words for plagiarism and 1,000 for AI checks, then Essential at 100,000 words a month and Professional at 200,000, billed monthly or yearly.
Bulk upload takes 20 files on Essential and 100 on Professional, and the site lists 17+ languages. Its privacy policy, last updated 14 October 2026, describes AI training on submitted content and licensing of aggregated data, and keeps aggregated data indefinitely.
What stands out
Free tier
Word-based plans
Bulk upload
Where it costs you
The privacy policy allows user content to feed AI training and licensed datasets, which rules it out for unpublished research.
Plans are metered by words per month, so heavy checking needs a larger allowance.
Right for
Freelancers and students wanting a free test tier before buying a monthly allowance
Wrong for
Authors handling unpublished or confidential manuscripts or contracts
Not stated by the vendorFree tier; monthly plans by word allowance, prices published
Credit-based scans built for publishers and SEO agencies
Ranked #6 of 11 in Best Plagiarism Checkers in 2026.
Free tierPublished pricingNorth America
Originality.ai is easy to start: a free allowance of 10,000 words arrives once, with no subscription. The ladder then runs from Pro at 200,000 words a month to Enterprise at 1.5 million, and extra seats are priced per seat.
Pay-as-you-go credits expire two years after purchase. Plans are sold directly on the vendor site by a company based in Collingwood, Ontario. Exit through PDF download and shared reports exists, but a bulk export is not described.
What stands out
Credit-based
Publisher focus
API on top plan
Where it costs you
Pro and Enterprise credits expire at month end, so unused volume is lost
API access is listed only on the Enterprise tier, which costs far more than Pro
Right for
Agencies and publishers scanning freelance copy in bulk and keeping scan history
Wrong for
Students checking one essay a term who gain nothing from team features
CanadaFree one-time credits; monthly plans by credits, prices published
Windows desktop checker with perpetual licences and cloud plans
Ranked #7 of 11 in Best Plagiarism Checkers in 2026.
Free tierPublished pricingNorth America
Plagiarism Checker X, LLC gives a New York address on its contact page. It sells in two ways: a downloadable Windows program with a limited free edition, a Professional licence for one user and a Business licence for five, and a newer cloud workspace with monthly Personal, Professional and Business plans metered in words.
Professional includes unlimited words and a year of maintenance. Reports can be exported as PDF in the cloud tiers.
What stands out
Perpetual licence
Windows desktop
Cloud plans
Where it costs you
The desktop edition runs on Windows only, so Mac users must switch to the cloud subscription.
Cloud plans cap words per month, and the pages do not describe the licence after the first maintenance year.
Right for
Individual writers who prefer paying once for a licence they install
Wrong for
Mac teams or anyone needing an LMS connection
United StatesFree limited edition; perpetual licences and monthly cloud plans, prices published
AI writing bundle with plagiarism checker as one included tool
Ranked #8 of 11 in Best Plagiarism Checkers in 2026.
Published pricingElsewhere
Smodin is quick to begin: paste text of 1,000 characters or more, or upload txt, doc, docx or pdf. The page claims 100+ languages, though the vendor admits its watermark check does not verify any provider's hidden key.
Starter and Premium are the paid tiers, and Premium removes usage limits. The company is Smodin LLC with a Dover, Delaware address. Check refund terms before paying, since the FAQ lists them as a question.
What stands out
Writing bundle
Subscription
Includes humanizer
Where it costs you
The accuracy figure is self-reported and no test set is named on the page
The company also promotes bypassing detectors, so its incentives point both ways
Right for
Students and writers who need many languages in one low-friction writing suite
Wrong for
Institutions needing audited accuracy, LMS integration and published rates
Not stated by the vendorMonthly or annual subscription with Starter and Premium tiers, prices published
Style editor where plagiarism checks are bought separately
Ranked #9 of 11 in Best Plagiarism Checkers in 2026.
Free tierPublished pricingEurope
The pricing page offers a free plan, a Premium plan, a higher Premium Pro plan and, on a separate toggle, a lifetime purchase. That range is unusual here, and lets a buyer cap the cost of ownership at a known figure.
The free plan is useful but limited per day. Premium removes the limits on rephrases and line-editing runs; Premium Pro adds live workshops and higher daily quotas on story tools. Its value lies in revision.
What stands out
Style editor
Extra-cost checks
Lifetime option
Where it costs you
The free plan is capped per day, with 10 rephrases and 2 runs of each report.
Generation is secondary: the product edits and critiques text more than it drafts new text.
Right for
Writers who revise their own drafts and want a lifetime licence option
Wrong for
Teams that need first drafts generated at volume
United KingdomFree, Premium and Premium Pro plans published; plagiarism checks cost extra
Writing assistant whose Pro plan adds plagiarism and AI detection
Ranked #10 of 11 in Best Plagiarism Checkers in 2026.
Free tierPublished pricingNorth America
The free plan covers spelling and grammar, tone reading and 100 AI prompts. Pro, offered with a free trial, adds full-sentence rewrites, tone adjustment, fluent English, unlimited suggestions, plagiarism and AI-text detection, and 2,000 prompts.
Enterprise adds proactive AI, custom roles, data loss prevention and customer-managed keys, and is sold through Superhuman Go. Its strength is breadth of placement, and its cost is that it sits inside a larger company's roadmap.
What stands out
Writing assistant
Pro tier only
Browser and desktop
Where it costs you
Free includes 100 AI prompts, and Pro caps text generation at 2,000 prompts.
Terms and privacy contact now sit with Superhuman Platform Inc., so the vendor is a wider suite.
Right for
Employees and students who want corrections inside every app they type in
Wrong for
Teams wanting marketing copy planned and generated at volume
United StatesFree plan without plagiarism check; Pro plan with 7-day trial; Enterprise quoted
Institution-wide checker with student paper repository, sold by quote
Ranked #11 of 11 in Best Plagiarism Checkers in 2026.
Pricing on requestNorth America
Turnitin fits an institutional rollout: Similarity, iThenticate, Gradescope, ExamSoft and Turnitin Clarity share a vendor, and regional sites cover many countries. Setup means a sales conversation, with no first-ninety-day price in public view.
Independence is low, because the product is bought through a contract and designed around institutional accounts. The company publishes false positive research, which helps a committee setting policy. Turnitin, LLC cites California law in its website terms.
What stands out
Institution licence
LMS integration
Quoted only
Where it costs you
No price list appears, and the pages offer a sales contact instead of a card checkout
Detector-only buyers face a platform contract with suite products attached
Right for
Universities needing AI findings inside the same system as similarity checks and grading
Wrong for
Freelancers and agencies wanting a self-serve detector with a card
United StatesQuoted per institution; contact sales, no prices on the product pages
A plagiarism checker is software that compares submitted text against web pages, published works and sometimes stored papers, and reports matching passages with their sources and a similarity score. The differences that matter are rarely in the feature list, so this is
the order we would work through them.
01
Decide whether you need a published price
10 of the 11 tools here publish what they cost; the other 1 quote per organisation. The ones you can compare without a sales call: PlagiarismSearch, Copyscape, Compilatio, Scribbr, Quetext, Originality.ai, Plagiarism Checker X, Smodin, ProWritingAid, Grammarly.
02
Decide how much the jurisdiction matters
These 11 vendors are established in 7 countries across 3 regions (North America 4, Europe 4, Elsewhere 3). That decides whose disclosure law applies to what the vendor holds, wherever the servers are.
Choosing a plagiarism checker by what it searches
The first split is the source set. Copyscape searches the public web, so it finds scraped pages but not a student paper handed in last year. Turnitin compares against a repository of student papers, archived web pages and publisher articles, which is why universities buy it. Scribbr states it checks 99 billion web pages and 8 million publications, while PlagiarismSearch gives no database size at all.
A checker that cannot see your type of source reports a clean document that is not clean. Run the same three samples through each trial: one copied web paragraph, one paraphrased passage and one passage from your own earlier work. Compare what each finds and how each labels the match.
Test a copied, a paraphrased and a self-reused passage in every trial
Ask the vendor which databases are searched, not how large the total is
Check whether your own earlier submissions can be added as a source
Per check, per word and per licence pricing
Plagiarism checkers charge in four ways. Scribbr bills per document by word count; Copyscape bills per search; Quetext, Originality.ai and Plagiarism Checker X meter words or credits per month; Turnitin is quoted per institution. Originality.ai uses two credits per hundred words when a scan covers both AI text and plagiarism, so its 2,000-credit plan covers about 100,000 words, not 200,000.
Grammarly puts the check in Pro only, while ProWritingAid sells checks as an extra on top of every plan. Estimate your yearly word count first, then price each option on that volume, including the second pass after every round of edits. Ask each vendor whether top-ups expire, because monthly credits at Originality.ai lapse at month end.
Convert each price into cost per 10,000 words on your own volume
Count rechecks after editing as new checks
Look for checks sold separately from the subscription
What happens to your uploaded text
Uploading a draft means handing over a document that may be unpublished. Scribbr says documents are never added to its database, and PlagiarismSearch says uploaded documents are not stored and that reports can be deleted. Quetext's privacy policy, dated 14 October 2026, allows AI training on submitted content and licensing of aggregated data, which rules it out for confidential manuscripts.
Institutional systems often keep submissions in a repository on purpose, so a student should know whether a paper will be stored for later comparison. Read the retention clause before the pricing page, and keep a copy of what you submitted. Ask a vendor in writing.
Read the privacy policy for AI training and data licensing clauses
Ask whether the checked document is stored or added to a repository
Find out whether reports and documents can be deleted by you
Schools, publishers and writers need different tools
A university needs an LMS connection and a repository, which points to Turnitin or Compilatio, whose Magister product connects to Moodle, Canvas, Brightspace, Blackboard and Microsoft Teams. A publisher checking freelancer copy needs batch scans, an API and team seats, which fits Copyscape and Originality.ai.
A single student or author needs a price per document and a clear privacy line, which is the Scribbr and PlagiarismSearch model. Smodin and Grammarly suit people who want the check inside a wider writing tool. Decide the buyer type before comparing prices, because the wrong type of product cannot be fixed by choosing a cheaper plan. Write the answer down before any trial.
Name the buyer: institution, publisher or individual
Check LMS, API or team-seat support at the tier you would buy
Ask a school vendor for a written institutional quote
What goes wrong most often when buying plagiarism checkers software
Trusting a clean result from a checker whose source set never included the document that was copied.
Comparing monthly prices without converting credits into words, so a combined AI and plagiarism scan uses up the allowance twice as fast.
Uploading an unpublished manuscript to a free tool without reading what its privacy policy says about AI training.
Treating a similarity percentage as a verdict, when properly quoted and cited passages also count as matches until a person reads the report.
07
Frequently asked questions
6 answers
What is the best plagiarism checkers in 2026?
PlagiarismSearch leads our ranking of 11. Sold as one-time packs and as monthly or three-month packages, so a student or editor can buy one check and leave. The site says uploaded documents are not stored and reports can be deleted.
A Spanish company operates it, yet a US entity is merchant of record for self-service card payments. Among monthly packages, API access starts at Standard, and no source database size is given.
Which plagiarism checkers tools publish their pricing?
10 of the 11, with the pricing model each one publishes:
PlagiarismSearch: Daily allowance after registration; one-time packs and monthly packages, prices published.
Copyscape: Pay per search, prices published; separate free comparison tool.
Compilatio: Student credit packs published; institutional licences quoted on request.
Scribbr: Price per document by word count, published; free check shows top sources only.
Quetext: Free tier; monthly plans by word allowance, prices published.
Originality.ai: Free one-time credits; monthly plans by credits, prices published.
Smodin: Monthly or annual subscription with Starter and Premium tiers, prices published.
ProWritingAid: Free, Premium and Premium Pro plans published; plagiarism checks cost extra.
Grammarly: Free plan without plagiarism check; Pro plan with 7-day trial; Enterprise quoted.
The other 1 quote per organisation.
Is there a free plagiarism checkers tool?
Quetext, Originality.ai, Plagiarism Checker X, ProWritingAid, Grammarly offer a free tier or a free self-hosted edition.
Where are these plagiarism checkers vendors established?
In 7 countries across 3 regions: North America 4, Europe 4, Elsewhere 3.
PlagiarismSearch: Spain.
Copyscape: Not stated by the vendor.
Compilatio: France.
Scribbr: Netherlands.
Quetext: Not stated by the vendor.
Originality.ai: Canada.
Plagiarism Checker X: United States.
Smodin: Not stated by the vendor.
ProWritingAid: United Kingdom.
Grammarly: United States.
Turnitin: United States.
What should you use instead of PlagiarismSearch?
Copyscape and Compilatio are the next two on this page. Copyscape is for Website owners and content managers checking pages for copies and finding scrapers; Compilatio is for European schools wanting a French-hosted plagiarism and AI checker with teacher and student editions.
Who should not buy PlagiarismSearch?
Universities needing a repository of earlier student work. Card payments for self-service packages are taken by a US company, so a European buyer contracts outside the EU..
If your plagiarism checkers product belongs among these 11, tell us what it does and who it is for. Inclusion is an editorial call; what a listing is and is not is set out under software advice.
