Everyone and their dog is pasting ChatGPT blurbs into essays. Teachers dread grading robots; bloggers fear Google penalties. You need a detector that says, "Yep, that paragraph's AI." Not a 2-page PDF of percentages.

Below are seven tools that actually caught my fake GPT-4 samples—ranked by how quickly they flagged the text, how clear the score felt, and how much they annoyed me with pop-ups.

Quick Take

AI content detector dashboard showing AI confidence scores and detailed explanations for flagged text sections

WriteHuman – Caught 8/10 GPT-4 snippets in under five seconds, dead-simple dashboard
StealthGPT – Free checker nails obvious AI, speed king at <2 s per 300 words
Winston AI – 99.98 % accuracy claim; love the teacher-style PDF reports.
GPTZero – Keeps up with new OpenAI models per recent benchmark.
BypassGPT – More a "humanizer," but its checker still spots sneaky phrasing.
Undetectable.ai – Aggregates multiple detectors, decent if you dig meta-scores.
StealthWriter – Dual humanizer/detector; flags lots of text but over-flags too.

(Want the longer SEO rant? Keep scrolling.)

1. WriteHuman – My Daily Driver

It just works. Paste text, get a blunt "Human / AI" bar. No login hoops.

WriteHuman: Quick-Check King

4.9

Fast flagging and a one-click rewrite if you need to humanize.

Pros:

✅ 8/10 GPT-4 hits in tests
✅ Sub-5-second scans
✅ Clean, ad-free UI

Cons:

❌ Free tier caps at 1,000 words/day
❌ No batch upload yet

Try WriteHuman

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2. StealthGPT – Speed Demon (Free)

If you're broke or in a hurry, run your text here first. It's the quickest checker I touched and still nabbed 7/10 tricky snippets. Big green "likely AI" banner = nice.

StealthGPT: Free & Fast

4.8

The slick free checker that nails the basics.

Pros:

✅ Real-time scanning under 2 s
✅ Generous free tier
✅ Clear traffic-light score

Cons:

❌ Less reliable on >1 K words
❌ GPT-centric focus

Try StealthGPT

We earn a commission if you make a purchase, at no additional cost to you.

3. Winston AI – Teacher Favorite

OCR uploads, PDF reports, and that bold 99.98 % accuracy pitch. In my test pack, Winston flagged 6.5/10 (rounded up for style points). Good pick if you grade essays all day.

Winston AI: Classroom Hero

4.3

Detailed reports & export-friendly PDFs for educators.

Pros:

✅ OCR for scanned docs
✅ PDF evidence reports
✅ Bulk upload

Cons:

❌ Slower (≈10 s/500 w)
❌ Premium plan needed for full export

Try Winston AI

We earn a commission if you make a purchase, at no additional cost to you.

4. GPTZero – Broad Coverage

GPTZero keeps pace with new LLM releases and stayed neck-and-neck with Winston in my tests. I still prefer its UI for quick vibes checks.

GPTZero: Model-Agnostic Checker

4.2

Covers GPT-3, GPT-4, Gemini, Claude—without drowning you in jargon.

Pros:

✅ Wide model support
✅ Handy highlight view
✅ Active dev updates

Cons:

❌ Free cap at 5K chars/day
❌ Occasional false positives on technical docs

Try GPTZero

We earn a commission if you make a purchase, at no additional cost to you.

5. BypassGPT – Edge-Case Specialist

Mostly marketed as a humanizer, but its checker caught 5/10 samples and gives a cool “risk slider.” Niche, yet handy for SEO pros playing cat-and-mouse.

BypassGPT: Niche Bypass + Check

3.9

For folks testing bypass tricks as much as detection.

Pros:

✅ Humanizer & checker combo
✅ CMS plugin options
✅ Risk-level slider

Cons:

❌ UI feels 2023
❌ Less accurate on long form

Try BypassGPT

We earn a commission if you make a purchase, at no additional cost to you.

6. Undetectable.ai – Meta-Score View

Instead of one model, Undetectable pings multiple detectors and averages the risk. Great if you want a second opinion without 10 browser tabs.

Undetectable AI: Meta-Detector

3.6

One scan, multiple detector opinions.

Pros:

✅ Aggregates GPTZero, CopyLeaks, more
✅ API for batch jobs
✅ Decent humanizer

Cons:

❌ Mainly a bypass tool
❌ Free trial locked at 250 words

Try Undetectable AI

We earn a commission if you make a purchase, at no additional cost to you.

7. StealthWriter – Dual Tool, Mixed Bag

StealthWriter rewrites and detects, but its checker over-flagged my genuine blog paragraph. Use it when you mainly need the humanizer (it’s pretty good).

StealthWriter: Rewrite-First Tool

3.7

Solid humanizer with an okay detector baked in.

Pros:

✅ 10-level humanizer slider
✅ Built-in plagiarism scan
✅ Affordable starter plan

Cons:

❌ Over-flags legit text
❌ Slow on >1 K words

Try StealthWriter

We earn a commission if you make a purchase, at no additional cost to you.

Pick One & Test It

Copy a chunk of your own ChatGPT text, run it through WriteHuman or StealthGPT, and watch the verdict. You’ll know in 30 seconds which detector fits your workflow.

Need more AI-marketing hacks? Check the deeper dive on /blog/seo-tools or pop over to our review of the /blog/best-ai-presentation-maker for slide geeks.