AI tools · Ranked by price to features
9 Best Free AI Detectors of 2026
By the Rankozo research desk · Updated November 12, 2026 · Next review December 27, 2026
GPTZero is the best free AI detector for teachers in 2026: its free plan scans 10,000 words a month and Premium costs $12.99 a month billed annually. Copyleaks suits editors who check long articles, with free scans of up to 25,000 characters; Scribbr is fully free with unlimited checks of up to 1,200 words and no account. Prices as of November 2026.
- Tools ranked
- 9
- With free plan
- 9
- Cheapest paid plan
- ZeroGPT, $8.99
- per month
By the numbers
- $20ChatGPT Plus costs $20 per month, billed monthly.OpenAI
- $17Claude Pro costs $17 per month on an annual plan ($200 billed up front) or $20 billed monthly.Anthropic
- $20A standard ChatGPT Business seat costs $20 per month billed annually or $25 billed monthly.OpenAI
- $30.00Microsoft 365 Copilot for enterprises costs $30 per user per month paid yearly as an add-on.Microsoft
- $2.6 billionGlobal edtech venture funding totaled $2.6 billion in 2025, and workforce companies captured nearly half of it, according to HolonIQ.HolonIQ by QS
Comparison table
| Tool | |||||
|---|---|---|---|---|---|
| GPTZero | 01 | 8.9 | 8.6 | $12.99per month | Yes |
| Copyleaks | 02 | 8.7 | 8.8 | $13.99per month | Yes |
| QuillBot AI Detector | 03 | 8.6 | 8.7 | Free plan | Yes |
| Scribbr AI Detector | 04 | 8.5 | 9.0 | Freeper month | Yes |
| Pangram | 05 | 8.4 | 8.0 | $20per month | Yes |
| ZeroGPT | 06 | 8.4 | 8.8 | $8.99per month | Yes |
| Grammarly AI Detector | 07 | 8.2 | 7.8 | Free plan | Yes |
| Originality.ai | 08 | 8.0 | 7.2 | $12.95per month | Yes |
| Sapling AI Detector | 09 | 7.9 | 7.8 | $12per month | Yes |
Click a column to sort. Prices are the cheapest paid plan quoted from each vendor's US pricing page; "Check price" means the US price check is pending.
How this ranking works
One method for every tool. We compared documented features and published prices; we did not run hands-on tests. Value carries the most weight.
Full methodThis list is for teachers and editors who want to check text for AI writing without paying and need to know how much text each free tool accepts. We compared documented features and published prices for 9 detectors and ranked them by value first, then features, then ease of use. Value weighs the free limit, per scan, per day or per month, against the price of the cheapest upgrade. Some vendors count words and others count characters; we report each limit the way the vendor states it. Prices are in USD as shown on each vendor's page on the check date; where a page showed only euros from our location, the price is marked pending. No detector is proof of AI use, and several vendors say so on their own pages.
The verdict
GPTZero is first because its free plan covers 10,000 words a month and its paid plans add class-scale tools such as 250-file batches and Canvas integration. Copyleaks is second for its 25,000 character free scans, and QuillBot is third with 6 free scans of up to 1,200 words a day. Scribbr is the pick when you want unlimited checks without an account, and ZeroGPT has the cheapest verified upgrade at $8.99 a month billed annually. Pangram, Grammarly, Originality.ai and Sapling each fit narrower needs.
- 01Top value
GPTZero
8.9/10An AI detector built for classrooms, with a free plan of 10,000 words per month and paid plans for heavier grading loads.
Price
$12.99per month
Free plan with 10,000 words per month; Premium from $12.99 per month billed annually
“PREMIUM MOST POPULAR $12.99 / month billed annually 300,000 words per month” Quoted from the pricing page, November 12, 2026.
- Free plan
- Yes
- Value (40%)
- 8.6
- Features (35%)
- 9.2
- Ease of use (25%)
- 8.8
Best forTeachers who scan a class set of essays each month
GPTZero ranks first because its free plan is generous for a teacher's monthly load and its paid plans are built around grading. The pricing page lists 10,000 words per month on Free, a basic AI scan and a small number of advanced scans, plus AI highlights in the Chrome extension. Premium costs $12.99 per month billed annually and raises the allowance to 300,000 words per month with a 50,000 character limit per scan, multilingual detection and downloadable AI reports. Professional, at $24.99 per month billed annually, adds 150,000 characters per scan, batch uploads of up to 250 files, page by page scanning and LMS integration for Canvas and Google Classroom. GPTZero says it is trusted by over 10 million teachers and students and names itself the official AI detector partner of the American Federation of Teachers. The free plan does not publish a per-scan cap, so very long theses may need splitting. We compared documented features and published prices; we did not run test documents.
- ✓The 10,000 free words per month cover several essays without a card
- ✓GPTZero is the official AI detector partner of the American Federation of Teachers
- ✓Team plans can be bought online without a sales call
- ✕The pricing page does not publish a per-scan cap for the free plan
- ✕Multilingual detection and downloadable reports are paid features
- ✕The Premium price shown is the annual rate
- Free allowance:
- 10,000 words per month
- Paid per-scan limit:
- 50,000 characters on Premium, 150,000 on Professional
- Cheapest paid plan:
- $12.99 per month billed annually
- LMS integration:
- Professional plan
Bottom line: GPTZero is the best free AI detector for teachers because its free plan covers 10,000 words a month. Upgrade to Premium at $12.99 a month when you grade more than a few classes.
- 02
Copyleaks
8.7/10An AI and plagiarism detector whose free web checker accepts up to 25,000 characters per scan.
Price
$13.99per month
Free scans up to 25,000 characters; Personal from $13.99 per month billed annually
“Cancel anytime. $167.88 billed annually.” Quoted from the pricing page, November 12, 2026.
- Free plan
- Yes
- Value (40%)
- 8.8
- Features (35%)
- 8.8
- Ease of use (25%)
- 8.4
Best forEditors who check long articles in one pass
Copyleaks is second because its free checker takes the longest single passage of any free tool here. The AI detector page says scans are free for up to 25,000 characters per scan and that signing up for a free account unlocks sentence-by-sentence insights and highlighted AI-written phrases. That suits editors who want to check a full feature article at once. The Personal plan costs $13.99 per month, billed as $167.88 a year, and includes 1,200 unified credits, which the vendor says covers up to 300,000 words or 1,200 images. It adds AI detection in 30+ languages, plagiarism detection in 100+ languages, multi-file uploads, a Google Docs add-on and MCP access. Pro, at $74.99 per month billed annually, includes 25 user seats and 3,000,000 words. Copyleaks claims a 0.03% false positive rate, which is the vendor's own figure. We compared documented features and published prices; we did not run test documents.
- ✓The 25,000 character free scan limit is the highest per-scan free cap in this list
- ✓A free account unlocks sentence-by-sentence insights and highlighted phrases
- ✓Paid plans combine AI and plagiarism results in one report
- ✕The pricing page does not list a free tier, only the web checker does
- ✕Paid credits are shared between text and image scans
- ✕The Personal price shown is the annual rate of $167.88 a year
- Free per-scan limit:
- 25,000 characters
- Cheapest paid plan:
- Personal, $13.99 per month billed annually
- Personal allowance:
- 1,200 credits, up to 300,000 words
- AI detection languages:
- 30+
Bottom line: Copyleaks is the best free AI detector for editors because one free scan accepts up to 25,000 characters. Its Personal plan adds plagiarism checks from $13.99 a month.
- 03
QuillBot AI Detector
8.6/10A free AI detector inside QuillBot's writing suite, with 1,200 words per scan and 6 scans a day.
Price
Free plan
Free plan; Premium is priced in euros from our location (USD check pending)
US price check pending. Vendor pricing page
- Free plan
- Yes
- Value (40%)
- 8.7
- Features (35%)
- 8.3
- Ease of use (25%)
- 9.0
Best forTeachers who check a few essays a day
QuillBot ranks third because it publishes the clearest free limits of any detector here. The AI detector page lists up to 1,200 words per scan and up to 6 scans per day on the free plan, with 1 free explainer card. Premium removes the word limit for detection scans, allows unlimited scans and gives detailed explainers across the full text. Text must be at least 80 words long, and QuillBot says that when a result is unclear its model tends to classify text as human written to reduce false positives. The page also tells users never to make an academic or employment decision on a detector score alone, which is sound advice for teachers. Premium bundles the paraphraser, grammar checker, humanizer and a plagiarism checker with 25,000 words a month. From our location the Premium page showed only euro prices, so the USD price is pending. We compared documented features and published prices; we did not run test documents.
- ✓A clear published limit: 1,200 words per scan and 6 scans per day
- ✓The detector leans toward a human verdict when results are unclear, which the vendor says reduces false positives
- ✓Premium also unlocks the paraphraser, humanizer and plagiarism checker
- ✕Free users get only 1 explainer card
- ✕Downloadable reports are Premium only
- ✕The Premium page showed only euro prices from our location
- Free per-scan limit:
- 1,200 words
- Free daily scans:
- 6
- Minimum length:
- 80 words
- Premium per-scan limit:
- No word limit
Bottom line: QuillBot is the best free AI detector for daily spot checks because it allows 6 scans of up to 1,200 words every day. Pick another tool if you need longer single scans for free.
- 04
Scribbr AI Detector
8.5/10A free AI detector from an academic writing service that needs no account and has no daily cap.
Price
Freeper month
Free; unlimited checks up to 1,200 words each, no paid AI detector plan listed
“Perform an unlimited number of AI checks for free, with a limit of up to 1,200 words per submission” Quoted from the pricing page, November 12, 2026.
- Free plan
- Yes
- Value (40%)
- 9.0
- Features (35%)
- 7.4
- Ease of use (25%)
- 9.3
Best forStudents and teachers who want unlimited checks without signing up
Scribbr is fourth because it is the simplest free option: no account, no daily cap and a published limit. The AI detector page promises an unlimited number of free AI checks with up to 1,200 words per submission, and says you can start without creating an account. It reports whether writing looks human-written, AI-generated or AI-refined, which helps teachers tell a paraphrased draft from a fully generated one, and gives paragraph-level feedback. Supported languages include English, German, French and Spanish. Scribbr states that submissions remain private and are not stored or shared. The tradeoffs are depth and length: there is no batch upload or report download on the page, and essays over 1,200 words must be checked in parts. The page itself notes that no AI detector can provide complete accuracy and suggests QuillBot's detector for a more advanced check. We compared documented features and published prices; we did not run test documents.
- ✓No account and no daily limit
- ✓Separates AI-refined text from fully AI-generated text
- ✓Scribbr says it does not store or share submitted text
- ✕The 1,200-word cap means longer papers must be split
- ✕No batch uploads or downloadable reports are listed
- ✕The page points users wanting a more advanced check to QuillBot
- Free per-scan limit:
- 1,200 words
- Daily limit:
- Unlimited
- Account needed:
- No
- Languages:
- English, German, French, Spanish
Bottom line: Scribbr is the best no-account AI detector because it allows unlimited free checks of up to 1,200 words each. Choose GPTZero or Copyleaks if you need reports or longer scans.
- 05
Pangram
8.4/10An AI detector focused on accuracy that gives free account holders twenty checks a day.
Price
$20per month
Free plan with 20 checks a day; Individual from $20 per month
“$0 for 7 days, then $20 per month” Quoted from the pricing page, November 12, 2026.
- Free plan
- Yes
- Free trial
- 7 days
- Value (40%)
- 8.0
- Features (35%)
- 8.9
- Ease of use (25%)
- 8.3
Best forEditors and publishers who check many short pieces
Pangram is sixth because it has strong documented features but the highest entry price among verified plans. Its FAQ says the free plan includes twenty free checks a day after signing up, including AI assistance detection, with plagiarism detection reserved for subscribers. The Individual plan costs $20 per month after a 7-day free trial and scans up to 300,000 words, 600 images or 50 minutes of video a month. It adds similarity detection on every scan, file upload with OCR for scanned documents, and Google Docs and Gmail integrations. Professional, at $65 per month, gives 5x more scans and $200 of API credits. Pangram says its detector supports 20+ languages and reports a false positive rate of 1 in 10,000, a figure calculated by the vendor on public datasets. The free plan's per-check length is not published on the pages we read. We compared documented features and published prices; we did not run test documents.
- ✓A daily free allowance suits editors who check many short submissions
- ✓Similarity detection is included on every paid scan
- ✓Pangram publishes a false positive rate of 1 in 10,000, its own figure
- ✕The highest starting price among verified paid plans here
- ✕The free plan's per-check word limit is not published on the pages we read
- ✕Plagiarism detection requires a subscription
- Free allowance:
- 20 checks a day
- Cheapest paid plan:
- Individual, $20 per month
- Individual allowance:
- 300,000 words a month
- Free trial:
- 7 days of Individual
Bottom line: Pangram is the best free AI detector for checking many short pieces because free accounts get twenty checks a day. Its paid plan starts at $20 a month, the highest here.
- 06
ZeroGPT
8.4/10An AI detector and writing toolkit whose free plan checks up to 15,000 characters per detection.
Price
$8.99per month
Free plan with 15,000 characters per detection; Pro from $8.99 per month billed annually
“PRO $ 8.99 /month $14.99 /month $107.88 /year” Quoted from the pricing page, November 12, 2026.
- Free plan
- Yes
- Value (40%)
- 8.8
- Features (35%)
- 8.0
- Ease of use (25%)
- 8.5
Best forBudget buyers who want the cheapest paid upgrade
ZeroGPT is fifth because it pairs a published free scan limit with the cheapest verified paid plan in this list. The pricing comparison table lists 15,000 characters per AI detection on the free plan and a 1,250,000-word monthly allowance, but no batch file checks. Pro costs $8.99 per month billed as $107.88 a year, or $14.99 month to month, and raises the limit to 100,000 characters per detection with 50 batch files, PDF reports and no ads. Plus at $13.99 and Max at $19.99 per month billed annually add plagiarism word allowances and 150,000 characters per detection on Max. Much of the subscription covers a paraphraser, summarizer, translator and chatbot that teachers may not need. Developers can use the API from $0.042 per 1,000 words. We compared documented features and published prices; we did not run test documents.
- ✓The cheapest verified paid plan here at $8.99 a month billed annually
- ✓A published free per-scan limit of 15,000 characters
- ✓Paid plans remove ads
- ✕Batch file checks are not available on the free plan
- ✕The free plan shows ads
- ✕Many paid features are writing tools unrelated to detection
- Free per-scan limit:
- 15,000 characters
- Pro per-scan limit:
- 100,000 characters
- Cheapest paid plan:
- Pro, $8.99 per month billed annually
- Monthly price:
- $14.99
Bottom line: ZeroGPT is the best budget AI detector because Pro costs $8.99 a month billed annually and checks 100,000 characters per scan. The free plan's 15,000 characters suit single essays.
- 07
Grammarly AI Detector
8.2/10A free AI detector from the Grammarly writing assistant that shows the share of text that appears AI-generated.
Price
Free plan
Free detector; Pro is priced in euros from our location (USD check pending)
US price check pending. Vendor pricing page
- Free plan
- Yes
- Value (40%)
- 7.8
- Features (35%)
- 7.8
- Ease of use (25%)
- 9.2
Best forWriters who already use Grammarly and want a quick score
Grammarly ranks seventh because its free detector is easy to use but publishes no scan limit and keeps the useful detail for Pro. The AI detector page explains the free flow: paste text or upload a document, click Scan for AI, and see what percentage of the text appears to be AI-generated. Grammarly Pro adds the AI Detector agent, which shows which parts may sound AI-generated and offers rewrites and citations. The Authorship feature categorizes text by source, such as AI, an online database or typed by the writer, which some teachers ask students to submit. Grammarly says its detector ranks first on the RAID benchmark; that is the vendor's own claim. The page also states that no AI detector can conclusively determine whether AI was used. No per-scan word limit is published, and the plans page showed only euro prices from our location, so the USD price is pending. We compared documented features and published prices; we did not run test documents.
- ✓Free to use with no published daily limit
- ✓Familiar for the 40 million people the vendor says use Grammarly
- ✓Authorship reports help students show how a draft was written
- ✕The page does not publish a per-scan word limit
- ✕Phrase-level highlights need Grammarly Pro
- ✕The plans page showed only euro prices from our location
- Free plan:
- Yes, overall AI percentage
- Per-scan limit:
- Not published
- Phrase highlights:
- Pro AI Detector agent
- File upload:
- Yes
Bottom line: Grammarly is the easiest free AI detector for existing Grammarly users because it scans pasted text or an uploaded file in seconds. Teachers who need phrase-level evidence should pick GPTZero.
- 08
Originality.ai
8.0/10A paid-first AI and plagiarism checker for publishers, with a small free allowance.
Price
$12.95per month
Free 10,000 words one time; Pro from $12.95 per month billed annually
“You will be billed yearly for an amount of: $155.4 ($12.95 x 12 months) instead of $179.4 ($14.95 x 12 months).” Quoted from the pricing page, November 12, 2026.
- Free plan
- Yes
- Value (40%)
- 7.2
- Features (35%)
- 9.0
- Ease of use (25%)
- 7.8
Best forPublishers and agencies that need scan history and team seats
Originality.ai is eighth because its free tier is small, even though its paid tools are broad. The pricing page lists a free plan with 10,000 words, or 100 credits, one time, and its comparison table shows a small daily credit allowance for free users. One credit covers 100 words. Pro costs $12.95 per month billed as $155.40 a year, or $14.95 month to month, and includes 200,000 words per month, bulk scans, shareable reports, PDF downloads, file uploads, 30-day scan history and team seats at $8.62 per month each on annual billing. The suite also covers plagiarism, readability, grammar, guideline and fact checks. For schools, Originality.ai offers a Moodle plugin, and its Chrome extension can replay how a Google Doc was written. Enterprise is $136.58 per month billed annually with API access. We compared documented features and published prices; we did not run test documents.
- ✓Every price on the page is listed in USD
- ✓Pro adds 30-day scan history and team seats
- ✓Combines AI, plagiarism, readability and fact checks
- ✕The free allowance is a one-time 10,000 words, plus a small daily credit
- ✕File uploads are a Pro feature
- ✕Enterprise jumps to $136.58 per month billed annually
- Free allowance:
- 10,000 words one time
- Cheapest paid plan:
- Pro, $12.95 per month billed annually
- Pro allowance:
- 200,000 words per month
- Credit size:
- 1 credit = 100 words
Bottom line: Originality.ai is the best paid upgrade for publishers because Pro includes 200,000 words a month for $12.95 billed annually. Its free 10,000 words are a one-time trial amount.
- 09
Sapling AI Detector
7.9/10A free AI detector from a writing assistant company that checks 2,000 characters at a time and scores every sentence.
Price
$12per month
Free plan with 2,000 characters per check; Pro from $12 per month billed annually
“$25 / month $12 / month, billed annually” Quoted from the pricing page, November 12, 2026.
- Free plan
- Yes
- Free trial
- 30 days
- Value (40%)
- 7.8
- Features (35%)
- 7.7
- Ease of use (25%)
- 8.2
Best forReviewers who want sentence-level scores in many languages
Sapling is ninth because its free limit is the tightest here, though its detector explains results well. The pricing page lists AI detector checks of up to 2,000 characters per check and 5 files per batch on Free, against 100,000 characters and 10 files on Pro. Pro costs $12 per month billed annually or $25 month to month, and new accounts get a free 1-month Pro trial. The detector shows an overall score and a score for each sentence from the same model; Sapling notes that a partly AI-written text can score low overall while some sentences score high. Supported languages include English, Spanish, French, German, Polish, Japanese, Arabic and Korean, 16 in total. Sapling also warns that no detector should be used as a standalone check. Enterprise starts at 10 seats at $15 per seat per month, and the API takes up to 200,000 characters per request. We compared documented features and published prices; we did not run test documents.
- ✓Shows a score for each sentence, which helps with partly AI-written text
- ✓A free 1-month Pro trial for new accounts
- ✓An API that accepts up to 200,000 characters per request
- ✕The 2,000 character free limit is the smallest per-scan cap here
- ✕Free batches are limited to 5 files
- ✕Monthly Pro billing is $25
- Free per-scan limit:
- 2,000 characters
- Pro per-scan limit:
- 100,000 characters
- Cheapest paid plan:
- Pro, $12 per month billed annually
- Languages:
- 16
Bottom line: Sapling is the best free AI detector for sentence-by-sentence scores because it rates each sentence as well as the whole text. Its 2,000 character free cap fits a paragraph, not an essay.
What to check before you pay
Check the free limit per scan
Free per-scan limits vary widely. Copyleaks takes up to 25,000 characters, ZeroGPT 15,000 characters, QuillBot and Scribbr 1,200 words, and Sapling 2,000 characters. A typical 1,500-word essay fits Copyleaks and ZeroGPT in one scan but must be split for QuillBot and Scribbr.
Check the daily or monthly allowance
Some tools cap volume instead of length. GPTZero allows 10,000 free words a month, QuillBot 6 free scans a day, Pangram twenty free checks a day, and Originality.ai a one-time 10,000 words. Scribbr lists unlimited free checks.
Decide whether you need an account
Scribbr works without signing up. GPTZero, Pangram and Originality.ai need a free account, and Copyleaks shows sentence-level insights only after you sign up for a free account.
Look for evidence beyond one score
A single percentage is weak evidence. Sapling scores every sentence, Scribbr separates AI-generated from AI-refined text, and Grammarly's Authorship report records where text came from. QuillBot, Sapling and Grammarly all state that a detector score should not be used on its own.
Know the upgrade price
Verified upgrade prices start at $8.99 a month for ZeroGPT Pro billed annually, $12 for Sapling Pro, $12.95 for Originality.ai Pro, $12.99 for GPTZero Premium and $13.99 for Copyleaks Personal, all billed annually, and $20 a month for Pangram Individual. QuillBot and Grammarly showed euro prices from our location, so their USD prices are pending.
FAQ
What is the best free AI detector?
GPTZero is the best free AI detector for most teachers in 2026. Its free plan scans 10,000 words a month, and Premium costs $12.99 a month billed annually if you need more.
Which free AI detector has the highest word limit per scan?
Copyleaks has the highest free per-scan limit in our list at 25,000 characters. ZeroGPT follows at 15,000 characters per detection, while QuillBot and Scribbr cap free scans at 1,200 words.
Is there a free AI detector with no sign-up?
Yes, Scribbr's AI Detector needs no account. It allows unlimited free checks of up to 1,200 words per submission and says it does not store or share your text.
How many free scans does QuillBot's AI detector allow?
QuillBot allows up to 6 free scans per day of up to 1,200 words each. Premium removes the word limit and allows unlimited scans.
Are free AI detectors accurate enough to accuse a student?
No. QuillBot says never to make an academic or employment decision on a detector score alone, Sapling says no detector should be used as a standalone check, and Grammarly says no detector can conclusively determine AI use.
What is the cheapest paid AI detector?
ZeroGPT Pro is the cheapest verified option at $8.99 a month billed annually, or $14.99 month to month. Sapling Pro is $12 a month billed annually and Originality.ai Pro is $12.95.
Is Grammarly's AI detector free?
Yes, Grammarly's AI detector is free and shows the percentage of text that appears AI-generated. Grammarly Pro adds an AI Detector agent that shows which parts may sound AI-generated.
Questions or corrections: editorial@rankozo.comSee our disclosure. Prices change; confirm on the vendor page before buying.
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