Eight AI detectors made this round's cut, and the sticker price is the least useful number on any of their pricing pages: cost per 100,000 words checked ranges from roughly $4.33 to $25, plagiarism checking is bundled on some, missing entirely on others, and shares one word pool with AI detection on a third, and a RAID-benchmark "#1" claim shows up on more than one vendor's site, each citing a different subset of the same data. Several of the eight also check images, not just text, but TruthScan goes further still, into documents, voice and video, and its own independent accuracy test tells a rougher story there than its text results do. The one fact every tool here shares gets less marketing attention: each of them sometimes flags writing a human actually wrote, and that risk runs measurably higher for non-native English writers.
Independent evidence vs. vendor claims
Search “AI detector accuracy test 2026” and most of what comes back is programmatic content-farm material: precise-sounding numbers like “600 text samples” or “47 documents,” with no visible author, dataset or methodology attached. Treat every number from that kind of source as unverified, not as journalism, wherever it turns up in this guide.
Two sources here clear a real independent-evidence bar. The RAID benchmark (ACL 2024) tested over 6 million generations across 11 generators and 12 adversarial attacks. At least five vendors in this category, Originality.ai, GPTZero, Grammarly, Desklib and It’s AI, separately claim to be “#1” or “most accurate” on RAID, each citing a different subset: clean text versus adversarial text, trained on RAID versus not. RAID itself is real; “we’re #1 on RAID” is a line nearly everyone in this category uses, each pointing at a different slice of the same leaderboard, and RAID’s public leaderboard didn’t load when we checked, so we couldn’t settle which claim is right.
The second is the Stanford HAI / Liang et al. TOEFL study (2023, still the most-cited work on this question through 2026), which tested seven commercial detectors on real non-native-English TOEFL essays and found a 61.3% average false-positive rate, one detector mis-flagging 97.8% of essays. When the same essays were rewritten with more elaborate AI-style vocabulary, the false-positive rate fell to 11.6%, which says something about what these tools are actually measuring. Originality.ai has published a rebuttal calling the study flawed; no vendor in this category has since published its own peer-reviewed non-native-English false-positive rate. Treat this as the strongest reason not to let any single detector score be the sole basis for an accusation against a non-native speaker.
A third data point, outside text altogether, backs up the same lesson. IDScan.net, an identity-verification vendor with its own competing document-authentication product, ran a structured test of TruthScan’s document checker across AI-generated IDs, legitimate IDs and traditional counterfeits, all photographed under matching conditions, and found a 57% false-positive rate on legitimate IDs alongside a 29% miss rate on AI-generated fakes, far short of TruthScan’s own 99% headline accuracy claim. Treat it the same way as the text-only findings above: a competitor-run test with a disclosed methodology, not a neutral academic study, but still more rigorous than most vendor marketing in this category.
Everything else in this guide, vendor-reported accuracy percentages, unnamed third-party rankings, even a semi-independent test like Scribbr’s own comparison (Scribbr sells a competing detector), is labeled by type in each tool’s section so you can weigh it accordingly.
All eight tools charge for checking content for AI involvement, but no two price it exactly the same way. Originality.ai, GPTZero and Copyleaks each meter a monthly word allowance in a fairly standard way. Pangram meters words too, at $20/mo for 300,000 words on Individual or $65/mo for 1,500,000 words on Professional. Winston AI meters “credits” that line up 1:1 with words on paper, behind a promo code that roughly halves the advertised price. Quetext also meters monthly words, but splits one pool between the Plagiarism Checker and the AI Detector rather than giving each its own allowance, so running both checks drains the same budget faster than a detector-only competitor’s pricing implies. Sapling breaks the word-allowance pattern entirely: it caps characters per single check rather than words per month, and bills one flat fee for, as far as we could confirm, unlimited checks. TruthScan runs the most layered system here: one dollar ladder, shown by default as $24/$83/$333 annual-billed monthly-equivalent rates, with two separate meters behind it, one credit per word for text and a separate “result” unit (one image or one PDF page) that works out to roughly 500 word-credits per check at every paid tier.
| Tool | Cheapest paid plan | Cost per 100k words | Free plan | Plagiarism check |  Trustpilot |  G2 |
|---|
| Originality.ai | $14.95/mo ($12.95/mo annual) | $7.48 / $6.48 | 10,000 words, one-time, no card | Yes, every tier | 4.5/5 (1,367) | 4.4/5 (240) |
| Pangram Labs | $20/mo | $6.67 | None, 7-day trial only | Similarity detection, not a plagiarism database | 3.3/5 (126) | None found |
| GPTZero | $12.99/mo annual-billed (true monthly price unpublished) | $4.33 (annual) | 10,000 words/mo, ongoing, no card | Separate product line | 2.1/5 (146) | 4.3-4.5/5 (101-120+, sources disagree) |
| Copyleaks | ~$13.99/mo annual (third-party, unverified against vendor) | $4.66 / $5.66 (third-party) | Not clearly advertised | Yes, 100+ languages | 2.6/5 (385) | 4.5/5 (41) |
| Winston AI | $9/mo with code WINSTON50 (list $18/mo) | $9.00 / $18.00 ($5.00 with code + annual billing) | 2,000 credits, 14-day trial | Yes, plus image/deepfake + OCR | 4.3/5 (24) | 4.4/5 (13) |
| Quetext | $14.99/mo | $14.99 | 1,000 words AI Detector + 1,000 plagiarism (monthly recurrence and card requirement both unconfirmed) | Yes, shares the AI Detector’s word pool | 4.6/5 (154) | 4.7/5 (13) |
| Sapling | $25/mo ($12/mo annual) | ~$12-25 flat per month, not metered by words | $0, 2,000 characters/check, no monthly cap found | No | 2.4/5 (7) | 4.2/5 (14) |
| TruthScan | $290/yr (~$24/mo annual-billed; month-to-month not listed) | ~$4.83 (annual, text) | 25 image/PDF results + 25,000 words/mo, no card | No | 1 review, not about the product | 4.8/5 (5) |
A few things the table can’t show on its own. Copyleaks’ dollar figures are third-party-sourced because its pricing page doesn’t show dollar prices, as of October 2026. Pangram’s page states its $20/mo and $65/mo prices directly; it just doesn’t show the annual-plan total, only that paying annually saves $60 a year on Individual or $240 on Professional. Sapling’s flat-fee framing assumes its unlimited-checks claim holds at real scale, which we couldn’t stress-test, and at 100,000 words a month, Sapling’s $25/mo (monthly billing) is the most expensive confirmed rate in this group; the flat fee only becomes a bargain at much higher volumes. Quetext’s $14.99 looks high next to the rest of this table because the Plagiarism Checker and AI Detector share one pool rather than separate allowances, and its advertised “40% off” annual discount never shows an actual dollar figure on the live page. TruthScan’s $4.83 is the annual-billed rate shown directly on its own pricing page; the true month-to-month price for that same Starter tier isn’t published anywhere we found, though the “2 months free” discount math TruthScan confirms for its Business plan would put it closer to $29/mo. Where the table says “plagiarism check: yes,” that’s a true plagiarism-database comparison against a reference corpus; Pangram’s similarity detection is a narrower check than that standard, and TruthScan’s “no” reflects that it checks for AI generation and manipulation, not matches against a reference corpus, so plagiarism was never part of its pitch.
Using a detector responsibly
Every tool in this guide sometimes flags writing a human actually wrote. The Stanford/Liang TOEFL study found this happens most often to non-native English writers: a 61.3% average false-positive rate across seven detectors on real TOEFL essays, one detector flagging 97.8% of them. Rewriting the same essays with more elaborate AI-style vocabulary cut that rate to 11.6%, which suggests these tools pick up something closer to writing style than true authorship.
That makes a single score from a single tool weak evidence on its own, whether you’re an editor deciding whether to publish, a hiring manager screening an application, or an instructor weighing an academic-integrity case. Run a borderline result through a second detector before acting on it, and weigh any score alongside something a detector can’t see: a document’s version history, a direct conversation with the writer, or a known sample of how that person usually writes. The same caution extends past text: TruthScan’s one independent, methodology-disclosed test found a 57% false-positive rate on legitimate IDs, so a detector flagging an image or a document deserves the same second look a flagged essay would get. None of the eight tools in this guide publish their own peer-reviewed false-positive rate for non-native English writers specifically; until one does, treat every score here as one input, not a verdict.
How we picked
Every price, limit and review score in this guide came from each vendor’s own pricing page where one was shown directly, as of October 2026. Copyleaks’ pricing page doesn’t show dollar prices at all, and Pangram’s page doesn’t show the annual-plan’s total dollar amount, only the monthly price and the savings from paying annually; both gaps are flagged in-line rather than presented as settled. TruthScan’s page shows an annual-billed monthly-equivalent price by default rather than a true month-to-month rate for its Starter and Professional tiers, a different kind of gap flagged the same way. G2 blocked direct access on most tools here, so those scores often come from search results instead and are labeled accordingly. Accuracy claims are split into three tiers throughout: independent evidence from a source with no competing product (RAID, the Stanford/Liang study, CyberNews’ detector tests), semi-independent tests from a source that sells its own competing product (Scribbr, IDScan.net), and vendor self-reported numbers. A claim never moves up a tier just because a vendor repeats it confidently.
Ranking here is editorial, not a function of which tool pays the highest commission. ToolsGavel may earn a commission if you sign up through a link on this page; that never changes which tool gets which badge.
Choosing by priority
There’s no single AI detector that wins on every axis in this comparison. Pick Originality.ai if you want plagiarism, grammar and fact-checking bundled with the AI check and the largest review base in this guide, and you’re comfortable checking for any recent model-update complaints before trusting today’s score. Pick Pangram Labs if a vendor’s stated commitment to low false positives matters more to you than a plagiarism bundle. Pick GPTZero if a standing monthly free tier matters more than its Trustpilot billing-complaint history. Pick Copyleaks if the job needs an API or LMS integration and you can tolerate pricing that comes from a third party rather than the vendor’s own page. Pick Winston AI if image and deepfake detection matter and you’re comfortable with a thin review sample. Pick Quetext if you want a plagiarism check and an AI check pulling from one scan and don’t mind the two features sharing a single word pool. Pick Sapling if a flat monthly fee beats a metered word allowance for your volume, and a missing plagiarism checker isn’t a dealbreaker. Pick TruthScan if you need to check images, documents or video for AI manipulation rather than just text, and you’ve read the independent ID-verification test before trusting its accuracy claims for that specific use case. Whichever you pick, read its full review before you rely on a single score.
Deals & price changes
Price changes and deals for AI content detectors
One short email when a tool in this guide changes its price or gets a verified deal. At most once a week.
Frequently asked questions
What's the cheapest AI detector in this guide?
By cost per 100,000 words, GPTZero's annual-billed Premium plan is the lowest confirmed figure in this guide at $4.33, followed by Copyleaks at roughly $4.66 (third-party sourced; Copyleaks' pricing page doesn't show dollar prices, as of October 2026) and TruthScan's Starter plan at about $4.83 on its own annual-billed rate, a figure shown directly on truthscan.com even though the true month-to-month Starter price isn't listed anywhere on the page. Pangram's Individual plan runs $6.67, Originality.ai's Pro plan runs $6.48 to $7.48 depending on billing term, and Sapling's flat $12-$25 a month lands higher still. Winston AI only drops to $5.00 per 100,000 words if its promo code is applied on top of annual billing; without both, it runs $9.00 to $18.00. Quetext's Essential plan runs $14.99 per 100,000 words, higher than every other metered detector's cheapest confirmed rate in this guide except Winston AI's $18.00 list price (without its promo code) and Sapling's $25/mo month-to-month fee (Sapling's $12/mo annual rate is lower), because Quetext's AI Detector and Plagiarism Checker draw from one shared word pool rather than separate allowances. None of these figures include a plagiarism check on the same terms except where noted, so the lowest price per word isn't automatically the lowest price for the job you actually need done.
Do any of these AI detectors offer a real free plan?
It depends how you define "real." GPTZero and TruthScan are the only two of the eight tools here with a free plan metered by a recurring monthly allowance rather than a one-time check or a trial: GPTZero gives 10,000 words every month, no card required, and TruthScan gives 25 image or PDF results plus 25,000 words every month, also no card required, though TruthScan's free tier is built around fraud-check use cases rather than writing checks. Originality.ai's Free gives a one-time 10,000-word check, also no card, but doesn't refill. Winston AI's Free is a 14-day trial of 2,000 credits, not an ongoing free tier. Sapling's Free has no monthly volume cap at all, just a 2,000-character limit per single check, run as many times as you want, as far as we could confirm. Quetext's Free gives 1,000 words for the Plagiarism Checker and 1,000 words for the AI Detector, plus 2,000 for the Summarizer and 500 for the Humanizer, but the pricing page doesn't say whether that allowance refills monthly or is a one-time amount, unlike Quetext's paid tiers, which explicitly state a monthly allowance. Pangram and Copyleaks don't advertise a standing free tier; Pangram offers a 7-day trial on a paid plan instead, and Copyleaks' pricing page doesn't clearly describe a free option either way.
Can I trust these tools' accuracy claims?
Treat vendor accuracy claims as marketing, not as test results, and treat most third-party "accuracy test" content you find by searching as unverified too. Only two sources meet a real independent-evidence bar: the RAID benchmark (ACL 2024) and the Stanford HAI / Liang et al. TOEFL study. At least five vendors in this category, Originality.ai, GPTZero, Grammarly, Desklib and It's AI, each claim to be "#1 on RAID," citing a different subset of the same benchmark, and RAID's public leaderboard didn't load when we checked, so we couldn't settle which claim is right. The safer approach is to run a borderline result through a second detector before acting on it, rather than trusting one vendor's number.
Which of these should I use if I'm worried about false-flagging a non-native English writer?
None of the eight tools in this guide publish their own peer-reviewed false-positive rate for non-native English writers specifically, and the one independent study that's tested this directly, the Stanford HAI / Liang et al. TOEFL study, found a 61.3% average false-positive rate across seven detectors on real non-native-English essays, with one detector flagging 97.8% of them. Originality.ai has publicly disputed that study's methodology rather than publishing its own number. For context, Turnitin, the dominant institutional plagiarism-and-AI tool and not ranked in this guide since it only sells through institutional contracts, states a sentence-level false-positive rate around 4% and a document-level rate under 1%, with a roughly 15% false-negative trade-off to get there, and a New York court still annulled an academic-integrity finding based on a Turnitin score on 2026-01-28. The safest approach with any tool here is the same: never let one score, from one detector, be the sole basis for a decision about a non-native English writer's work.
