Best AI Detector in 2026: 9 Top Picks Compared

The best AI detector in 2026 is Essai. It is free to use, gives a clear AI probability score from 0 to 100 percent, and a free account adds detailed reports and unlimited scans. When a draft gets flagged, Essai's built-in AI humanizer lets you revise it and check again in the same app.

Below, we rank nine popular AI detectors, including GPTZero, Originality.ai, Copyleaks, Winston AI and ZeroGPT, on what you get for free, what you pay, the limits on each plan and what users report. Each entry links to our full review, so you can dig deeper before you choose.

Best AI detector rankings for 2026

Prices are in US dollars as of October 2026.

How we ranked them

We ranked each AI detector on five things that matter when you check your own writing: how much you can scan for free, what paid plans cost, the limits and credit rules on each plan, the tools you get for checking and fixing a draft, and public user feedback on sites like Trustpilot. We also weighed Essai's internal testing, in which our detector outperformed other popular AI detectors on many of the criteria we track. Facts about each competitor come from its public pricing, help and review pages as of October 2026.

The top 9 AI detectors in detail

1. Essai: best AI detector overall

Best for: students, writers and marketers who want unlimited free checks and a fast way to fix what gets flagged.

Essai's AI detector returns an AI probability score from 0 to 100 percent and works best on 150 words or more. It is free to use, and a free account adds detailed reports and unlimited scans, so there are no daily caps, monthly word allowances or credits to track.

The same app includes Essai's AI humanizer, which is designed to keep your meaning while making phrasing, rhythm and word choice read naturally. Check a draft, humanize the passages that read as machine-written, and check again without switching tools.

Key facts (as of October 2026): unlimited AI detection on a free account; humanizer free up to 125 words per request with no signup or credit card; Basic at $14.99/month, or $9.99/month billed yearly, with 5,000 words a month, up to 500 words per request and unlimited AI detection; Pro and Ultra for bigger workloads, listed on the Essai pricing page.

Pros

• Unlimited scans and detailed reports on a free account.
• Detector and humanizer in one app, so you can fix a flagged draft without switching tools.

Cons

• Works best on 150 words or more, so paste at least a full paragraph.
• Free humanizer requests stop at 125 words; longer rewrites need a paid plan.

If rewriting is your main job, see our ranking of the best AI humanizers.

2. GPTZero: best for classroom integrations

Best for: schools that want writing replays and LMS integrations.

GPTZero labels text as human, mixed or AI, highlights the sentences behind the verdict and shows a confidence score. Its homepage says it is now part of Superhuman, the company behind Grammarly.

Key facts (as of October 2026): free plan of 10,000 words a month; Premium at $23.99/month, or $12.99/month billed yearly, with 300,000 words a month; Canvas and Google Classroom integration only on Professional at $45.99/month.

Pros

• Clear three-way verdicts with sentence highlighting.
• Writing Replay shows how a Google Doc was typed, edited and pasted.

Cons

• Tight free plan: one Advanced Scan, no downloadable reports and batches of three files.
• No AI humanizer, so fixing a flagged draft means switching to another tool.

Read our full GPTZero review.

3. Originality.ai: best for publishers

Best for: publishers and agencies that screen freelance copy at volume.

Originality.ai is a credit-based AI detector and plagiarism checker. Its AI Allowance setting lets you choose how much AI help is acceptable, from 0 to 40 percent, before a document is labeled Likely AI.

Key facts (as of October 2026): free checker with 3 AI scans a day of up to 2,000 words each; Pro at $14.95/month, or $12.95/month billed yearly, with 2,000 credits a month; one credit covers 100 words of AI checking; API access only on Enterprise at $179/month.

Pros

• AI detection, plagiarism checks and readability tools in one app.
• Adjustable strictness through AI Allowance.

Cons

• Its own help center says editing with Grammarly, Quillbot, ChatGPT or Microsoft Word Editor can raise the AI score of text you wrote yourself.
• Subscription credits expire at the end of each billing month, and running AI and plagiarism checks together doubles the cost.

Read our full Originality.ai review.

4. Copyleaks: best for AI plus plagiarism checks

Best for: schools and businesses that want AI and plagiarism findings in one report.

Copyleaks shows what share of a text is likely AI-generated, detects AI text in 30 languages and adds plagiarism checks on its paid plans.

Key facts (as of October 2026): no-login AI scans of up to 25,000 characters; Personal at $16.99/month, or $13.99/month billed yearly, with 100 credits a month; one credit covers up to 250 words.

Pros

• AI and plagiarism results in a single report.
• AI detection in 30 languages.

Cons

• Credits round up: every started block of 250 words costs a full credit, and unused monthly credits are canceled at month end.
• Its privacy policy lists model training among the uses of scanned content, and opting out means contacting support.

Read our full Copyleaks review.

5. Winston AI: best for PDF reports and OCR

Best for: teachers and editors who need shareable reports, including for handwritten pages.

Winston AI rates text with a Human Score from 0 (likely AI) to 100 (likely human), colors each passage on an AI Prediction Map and reads photos and handwriting through OCR.

Key facts (as of October 2026): a 14-day free trial with 2,000 credits; Essential at $18/month, or $120/year; AI detection costs 1 credit per word and plagiarism 2; plagiarism checks start on Advanced at $29/month.

Pros

• Sentence-level AI Prediction Map and PDF reports on paid plans.
• OCR for photographed and handwritten work.

Cons

• No free plan after the trial, and unused credits reset every billing cycle.
• Winston's own terms say a score of 90 "may mistakenly label content as AI-generated approximately 1 time out of every 10."

Read our full Winston AI review.

6. QuillBot: best for an all-in-one writing suite

Best for: writers who want a paraphraser, grammar checker and detector under one subscription.

QuillBot's AI detector returns a 0 to 100 percent AI likelihood with sentence highlights, and the suite adds a paraphraser, grammar checker, AI humanizer and plagiarism checker.

Key facts (as of October 2026): free detection of up to 1,200 words per scan, six scans a day; Premium at $19.95/month, or $8.33/month billed yearly ($99.95/year); plagiarism checks only on Premium.

Pros

• Many writing tools in one plan.
• Sentence highlights and explainer cards on detector results.

Cons

• Free detection stops at six scans a day, and free humanizing stops at 100 words.
• QuillBot's Trust Center says user inputs are used to train and personalize its services.

Read our full QuillBot review.

7. Grammarly AI Detector: best for existing Grammarly users

Best for: people who already use Grammarly and write in Google Docs or Word.

Grammarly's free AI checker shows what share of your text appears AI-generated. Paid plans add an AI Detector agent that marks flagged sections and runs checks inside Google Docs and Word.

Key facts (as of October 2026): free web checker with file upload and one overall score; Pro at $30/month, or $12/month billed yearly.

Pros

• Free check with file upload.
• Detection inside Google Docs and Word on paid plans.

Cons

• The free checker gives one overall score; seeing which passages were flagged takes a paid plan.
• Its help center warns that rewrites from Grammarly's own AI agents will likely be flagged by its detector.

Read our full Grammarly AI Detector review.

8. Sapling AI Detector: best for developers

Best for: teams that need an API or bulk checks.

Sapling returns an overall AI-generation score plus sentence scores, reads PDF and Word files, covers eight languages and offers a well-documented API.

Key facts (as of October 2026): free checks score only the first 2,000 characters; Pro at $25/month, or $12/month billed yearly, checks up to 100,000 characters at a time; API from $0.005 per 1,000 characters.

Pros

• Sentence-level scores, even on the free tier.
• REST API and SDKs for developers.

Cons

• Free checks cover only the first 2,000 characters, so a full essay is only partly scored.
• AI detection in its Chrome extension becomes a paid feature after the first month.

Read our full Sapling AI Detector review.

9. ZeroGPT: best for quick second opinions

Best for: occasional free checks when you want a second opinion.

ZeroGPT returns an overall AI percentage with highlighted sentences and bundles a humanizer, plagiarism checker and other writing tools under one login.

Key facts (as of October 2026): free checks of up to 15,000 characters, with ads; Pro at $14.99/month, or $8.99/month billed yearly (US prices); refund requests must arrive within 10 hours of a first subscription purchase.

Pros

• Roomy free checks of up to 15,000 characters.
• Many writing tools under one account.

Cons

• In 2023, Ars Technica published screenshots of ZeroGPT labeling part of the US Constitution as AI-generated.
• The free tier shows ads and leaves out PDF reports and scan history.

Read our full ZeroGPT review.

AI detector comparison: Essai vs the runner-ups

Here is how our top pick compares with the next three detectors on the points that matter most when you check your own writing, as of October 2026.

Essai comes out ahead on every row: unlimited free scans with an account, no credits to count on paid plans, a humanizer in the same app and the lowest yearly price of the four. That mix is why it tops our list.

How to choose the best AI detector for you

Use these checks to compare any AI detector, including the ones on this list.

• Start with the free limits. Daily caps (six scans on QuillBot, three on Originality.ai), monthly caps (10,000 words on GPTZero), short trials (14 days on Winston AI) and partial scoring (the first 2,000 characters on Sapling) decide how often you can check a draft. Essai's free account has unlimited scans.
• Pick a score you can act on. A single AI probability from 0 to 100 percent, like Essai's, tells you at a glance whether a draft needs work.
• Avoid credit math. Credits that round up (Copyleaks), expire monthly (Originality.ai and Winston AI) or cost one per word (Winston AI) make the real price hard to predict. Every paid Essai plan includes unlimited AI detection.
• Give the detector enough text. Essai works best on 150 words or more. Winston AI recommends 300 or more, and Originality.ai's website needs at least 100.
• Plan for the fix, not just the flag. A detector tells you a draft reads as AI-written. Essai's humanizer helps you revise it in the same app, while GPTZero, Copyleaks, Winston AI and Sapling list no humanizer.
• Read every score as a signal. In a 2023 Stanford study, early versions of seven popular detectors, GPTZero, Originality.ai, ZeroGPT and Sapling among them, labeled more than half of 91 essays by non-native English writers as AI-generated on average. Keep your drafts and version history, and see our guide to AI detection false positives if your own writing gets flagged.

What users say

Public reviews of several well-known detectors repeat the same complaints: human writing flagged as AI, and billing surprises. As of October 2026:

• GPTZero: a TrustScore of 2.1 from 145 reviews on Trustpilot, half of them one-star. Reviewers describe human writing flagged as AI, charges after a free trial or for an annual plan they did not expect, and hard cancellations.
• Copyleaks: a TrustScore of 2.7 from 365 reviews on Trustpilot, nearly half of them one-star. Recent complaints include human writing flagged as AI, ChatGPT text that went undetected and results that changed from one scan to the next.
• ZeroGPT: a TrustScore of 1.2 from 111 reviews on Trustpilot, nearly all of them one-star. Most recent reviews describe human-written essays flagged as AI and scores that swing after small edits.

What Essai users say

"I've tested many alternatives, but nothing comes close to the quality Essai provides." (Priya Sharma, Essai user)

"Essai has revolutionized my business management studies. The text humanizer has significantly improved my reports and presentations. This all-in-one solution is a student's dream!" (David Williams, Essai user)

Verdict

Essai is our pick for the best AI detector in 2026, for students and writers alike. It is free to use, a free account adds unlimited scans and detailed reports, and every paid plan includes unlimited AI detection, so you never ration checks or count credits. The built-in humanizer turns a flagged result into a revised draft without leaving the app. GPTZero, Originality.ai and Copyleaks round out the top four, but none matches Essai's mix of unlimited free checks and built-in humanizing. Create a free account and run your next draft through Essai.