Visibility in this ranking can be paid for. Payment gives a vendor more visibility, higher up on the review pages; it never adds a vendor, and it never changes a word of the review. The largest vendors in AI content detectors and plagiarism checkers
cannot hold places 1 to 3. 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. How it works: placement disclosure ·
editorial process.
The 13 tools, reviewed
#1 Pangram
AI text detector with published plans and a no-training promise · United States · pangram.com
Published prices SOC 2 Type II No training on submissions
Pangram earns first place on how plainly it sells. The pricing page lists an Individual plan at $20 a month with a seven-day trial, a Team plan at $20 per seat with two seats minimum, and a Professional plan at $65 that bundles $200 of API credits.
- Pricing: Per user / month. Individual is $20 a month for 300,000 words and 100 image scans, Team is $40 a month for two seats, Professional is $65 a month with $200 of monthly API credits. Free plan: free plan.
- Best for: Editors and teams that want a clear price
- Strengths: AI text detection; AI image detection; Similarity detection.
Where it falls short
Word caps apply per plan: 300,000 words a month on Individual, five times that on Professional. Content stays on Pangram's servers until you delete it or close the account.
Wrong for
A university that needs a campus-wide agreement with grading-system integration and a plagiarism corpus built over decades.
Visit Pangram →
#2 Winston AI
AI text and image detector with a plagiarism scan · Canada · gowinston.ai
Text and image detection Montreal company Credit-based tiers
Winston AI covers more ground than most single-purpose detectors, and every tier shows its price. Essential gives 100,000 credits a month, Advanced 200,000 with up to five team members, and Elite 500,000 with unlimited members. All tiers include text detection, image and deepfake checks, document scanning and OCR for handwriting.
- Pricing: Per user / month. Free start with 2,000 credits for 14 days. Free plan: free trial.
- Best for: Publishers and teachers checking text and images
- Strengths: AI text detection; AI image and deepfake detection; Plagiarism detection.
Where it falls short
The pricing page counts in credits without explaining how many credits a given document uses, so the monthly allowance is hard to translate into articles.
Wrong for
A school district that needs a signed data processing agreement and LMS roll-out support; ask Compilatio or Turnitin.
Visit Winston AI →
#3 Compilatio
French plagiarism and AI checker for schools · France · compilatio.net
Registered in France Education focus LMS and SSO integration
Compilatio is the pick for an institution that wants its student papers handled by a European company. Its legal notice names COMPILATIO SAS, registered in the Annecy trade register with its seat in Chavanod, France, and an Italian arm in Turin. Magister is the teacher product and Studium lets students check their own drafts before they submit.
- Pricing: Quote only. No prices published; Magister for educators and Gingo are sold on request, and students can create a free Compilatio Studium account. Free plan: none.
- Best for: European universities wanting a Turnitin alternative
- Strengths: Plagiarism detection; AI text detection; Altered text detection.
Where it falls short
Pricing is by demo request, so a small agency or a freelance editor cannot compare cost. The product is built around classrooms, which means workflows for content teams, bulk URL scans and website monitoring are not what it is for.
Wrong for
A marketing team that wants to scan freelancer drafts for copied web content, where Copyscape or Originality.ai fit better.
Visit Compilatio →
#4 Originality.ai
AI and plagiarism checker built for web publishers · Canada · originality.ai
Publisher workflows Credit packs Opt-out from training
Originality.ai is built around the publisher who buys articles from freelancers. You paste a URL, upload a file or scan a whole site, and the report can be shared by link or downloaded.
- Pricing: Per user / month. Pro is $12.95 a month billed annually ($14.95 monthly) for 200,000 words. Free plan: free plan.
- Best for: Content agencies auditing freelance writers
- Strengths: AI detection; Plagiarism checker; Fact and hallucination checker.
Where it falls short
The privacy policy says that, unless you opt out, scan history and results may be used to train and improve its models. Student data under an institutional agreement is excluded from general AI training.
Wrong for
A law firm or newsroom whose drafts are confidential and cannot be used for model training by default.
Visit Originality.ai →
#5 Copyscape
Pay-per-check web plagiarism search with monitoring · Gibraltar · copyscape.com
Pay per search Private index Page monitoring
Copyscape answers a different question than most of this list: has this text already appeared on the web. Premium bills only what you use, 3 cents for the first 200 words and 1 cent for each further 100, and the API costs the same as the web interface.
- Pricing: Usage-based. Premium searches cost 3 cents for the first 200 words plus 1 cent per additional 100 words. Free plan: free plan.
- Best for: Webmasters protecting live pages from copying
- Strengths: Web plagiarism search; Premium AI detector; Batch search.
Where it falls short
The AI detector is a minor feature next to the search. Copyscape's own FAQ warns against taking disciplinary action on its score. It compares against public web pages, so it will not see copying from closed student repositories.
Wrong for
A school that needs to check student essays against past submissions and journals, where Turnitin or Compilatio hold that kind of corpus.
Visit Copyscape →
#6 Inspera Originality
Similarity and AI flags inside a Norwegian exam platform · Norway · inspera.com
Founded in Oslo Configurable risk levels Student pre-checks
Inspera Originality is the product behind what used to be sold as Crossplag; crossplag.com now loads Inspera's own site. The company describes itself as founded in 1999 in Oslo, with offices listed for Norway, Sweden, Denmark and the UK. Its page promises configurable thresholds and risk levels instead of a bare percentage, and reports students can see before they submit.
- Pricing: Quote only. No prices published; Book a Demo is the only route, and the module is sold with Inspera Assessment or integrated into an LMS. Free plan: none.
- Best for: Universities already on Inspera Assessment
- Strengths: Similarity detection; Cross-language translation; AI authorship flags.
Where it falls short
The pages give no price, no corpus size and no accuracy detail, so a buyer is comparing a brochure.
Wrong for
A business checking contractor copy or SEO articles.
Visit Inspera Originality →
#7 Sapling
Writing assistant with an AI detector and metered API · United States · sapling.ai
Detector API Per-check character cap Self-hosting option
Sapling is a writing assistant first and a detector second, and that suits a support team already pasting replies into it. The free plan scans up to 2,000 characters per check with five files per batch; Pro lifts that to 100,000 characters and ten files, and adds Rephrase and unlimited snippets.
- Pricing: Per user / month. Free covers 2,000 characters per check. Free plan: free plan.
- Best for: Developers and support teams checking short text
- Strengths: AI detector; Grammar check; Rephrase.
Where it falls short
A detector bolted onto a grammar tool has no plagiarism database, no student workflow and no site scans. The free cap of 2,000 characters is a few paragraphs.
Wrong for
A school or publisher that needs plagiarism and AI checks in one report with sources shown.
Visit Sapling →
#8 GPTZero
AI detector and writing replay for classrooms · United States · gptzero.me
Writing Replay SOC 2 Type II Classroom focus
GPTZero is placed eighth because it is the most visible detector in schools, and the order keeps the biggest names out of the top three. Its distinct feature is Writing Replay, which records a document being written, shows pasted text and flags unnatural typing, so an accusation can rest on process, not only a score.
- Pricing: Per user / month. Free scanner up to 10,000 characters. Free plan: free plan.
- Best for: Teachers who want process evidence
- Strengths: AI detector; Writing Replay; Plagiarism checker.
Where it falls short
The pricing page shows placeholder zeros when fetched, so published prices could not be confirmed for this ranking. Team plans accept card payment only; purchase orders go through sales.
Wrong for
A company reviewing candidate cover letters or freelance drafts, where the replay requires writers to cooperate.
Visit GPTZero →
#9 Turnitin
Institutional similarity checking with an AI add-on · United States · turnitin.com
Quote only Large source database LTI 1.3
Turnitin belongs on any institutional shortlist, and the order keeps it out of the top three only because most readers are not a university. Its Similarity Report compares work against student submissions, premium publications and more than 20 years of web content, in 170 languages, with a flags panel for hidden or replaced characters.
- Pricing: Quote only. No prices published; Turnitin Similarity is quoted per institution, and Turnitin Originality adds AI writing and AI paraphrasing detection. Free plan: none.
- Best for: Universities needing a large source corpus
- Strengths: Similarity Report; Flags panel; AI writing detection.
Where it falls short
Everything is by quote, and AI detection costs extra on top of similarity. The corpus is partly built from student submissions, so papers enter a repository the vendor controls; ask about retention and deletion.
Wrong for
A publisher or agency without an LMS.
Visit Turnitin →
#10 Copyleaks
Plagiarism, AI and code detection via a single API · United States · copyleaks.com
API first SOC 2 and SOC 3 EU data site
Copyleaks is the broadest toolbox for a developer. Its documentation lists endpoints for plagiarism in text and code, AI text and image detection, a grammar checker, a citation checker that looks for fabricated references, and text moderation, with SDKs in six languages.
- Pricing: Quote only. Pricing page blocked our fetch; self-serve and enterprise tiers exist, and figures are not verified here. Free plan: free trial.
- Best for: Developers and institutions needing an API
- Strengths: AI text detection; AI image detection; Plagiarism in text.
Where it falls short
We could not fetch the pricing page, the about page or the terms, so no price, entity address or training policy is confirmed here. The breadth also means a simple buyer faces many products and credit types.
Wrong for
A solo blogger who wants one page and a price.
Visit Copyleaks →
#11 Grammarly
Writing assistant with plagiarism and AI checks in Pro · United States · grammarly.com
Part of Superhuman Pro only for detection Authorship tracking
Grammarly is the least dedicated detector here, listed for readers who already pay for it. Its plans page shows Free at €0 and Pro at €12 in the currency served to us; the comparison table marks AI text detection and plagiarism as included only from Pro, and Enterprise adds BYOK encryption, SCIM and data loss prevention.
- Pricing: Per user / month. Free €0. Free plan: free plan.
- Best for: Individuals who already use Grammarly
- Strengths: Plagiarism detection; AI text detection; Authorship tracking.
Where it falls short
Detection is a side feature, and its pages describe no corpus size, sample size or detection method in the pages we read. The free plan has no plagiarism or AI check.
Wrong for
A publisher auditing freelancers, or a school grading submissions.
Visit Grammarly →
#12 ZeroGPT
Free AI detector with a bundle of text tools · United States · zerogpt.com
Free tier API pay as you go Wyoming LLC
ZeroGPT is the one most people meet first, because the free detector works without an account. The site adds a plagiarism checker, an image detector, a video detector and writing tools such as a paraphraser and summarizer, and the API is pay as you go with a balance topped up in the dashboard.
- Pricing: Per user / month. Free forever tier. Free plan: free plan.
- Best for: Casual users wanting a quick free check
- Strengths: AI/GPT detector; Plagiarism checker; AI image detector.
Where it falls short
The same site sells an AI humanizer whose purpose is to make AI text read as human, which pulls against the job of a detector.
Wrong for
A publisher, school or employer making decisions about people.
Visit ZeroGPT →
#13 Smodin
Student writing suite with detector and humanizer · United States · smodin.io
Bundled AI writer Humanizer included Plans in USD
Smodin is a student toolkit that happens to include a detector. The pricing page promises Starter with every tool unlocked and Premium with unlimited output, advanced models, a Chrome extension and API access, plus a mock interview and cover letter toolkit.
- Pricing: Per user / month. Starter and Premium plans, monthly or annual with 20 percent off, in USD; prices were not in the page text we read. Free plan: none.
- Best for: Students wanting all tools in one subscription
- Strengths: AI content detector; AI humanizer; Plagiarism checker.
Where it falls short
The vendor sells an AI humanizer, with wording that Starter lets you detect and bypass top AI detectors, so its detector exists partly to help users beat other detectors.
Wrong for
Anyone assessing other people's writing: a teacher, an editor or an HR team.
Visit Smodin →
Questions and answers
What is the best AI content detector in 2026?
Pangram ranks first of 13, best for editors and teams that want a clear price. Winston AI is second (publishers and teachers checking text and images) and Compilatio third (european universities wanting a Turnitin alternative). Places 1 to 3 go to challengers, vendors outside the best-known brands, wherever the category has them.
Can an AI detector prove that a person used ChatGPT?
No. Copyscape's own FAQ says not to take disciplinary action based on its AI detector, Turnitin states that its similarity score does not decide whether plagiarism happened, and Inspera says its flags inform judgment but do not replace it.
What is the difference between an AI detector and a plagiarism checker?
A plagiarism checker looks for text that already exists elsewhere, in web pages, publications or earlier student papers. An AI detector estimates whether the style of new text looks machine-generated, even when no source exists.
How much does AI detection cost per month?
Published entry prices on the pages we read: Pangram $20, Winston AI $18 on monthly billing, Originality.ai $14.95 on monthly billing or $12.95 annually, Sapling $12 annually, Grammarly Pro €12.
Is there a free AI detector worth using?
GPTZero, ZeroGPT, Sapling, Pangram, Winston AI and Originality.ai each have a free tier or trial, with limits such as 2,000 characters per check on Sapling or 2,000 credits for 14 days on Winston AI.
Which AI detectors are used by universities?
Turnitin, Compilatio and Inspera Originality sell directly to institutions, with LMS plug-ins and single sign-on, and all three give no public price. GPTZero also integrates with Canvas and Google Classroom. Pangram lists LMS integrations and a university page.
Do detectors store the text I submit?
Yes, in most cases. Pangram keeps submitted text while the account is active and deletes it when you remove it from history. Originality.ai keeps scan history and says it may use it to train models unless you opt out.
Are there European AI detectors?
Compilatio is French, registered in Annecy, and Inspera Originality comes from Oslo; both sell to institutions by quote. Scribbr, a Dutch company on the usual lists, blocked our fetch, so it is not ranked.
Can a humanizer make AI text pass a detector?
Vendors say so, and some sell it. ZeroGPT and Smodin offer AI humanizers, and Smodin's pricing page says Starter lets you detect and bypass top AI detectors. That is a conflict of interest for a detector vendor.
Should I run text through several detectors?
Running two is reasonable when a result will start a conversation with a writer, since a lone score is hard to defend.
Does Grammarly detect AI text?
Yes on the Pro plan, which the comparison table lists as including detection of AI-generated text and accidental plagiarism, plus Grammarly Authorship to label where text came from. The free plan has neither.
