AI draft
Sleep plays a crucial role in memory consolidation, serving as a cornerstone of effective learning. Notably, participants who slept eight hours recalled 23% more word pairs (Okafor, 2023), underscoring the vital importance of rest.
HumanGPT vs GPTZero: a rewriter and a detector compared
GPTZero is an AI detector with tools for educators, such as a Hallucination Detector and Writing Replay for Google Docs.1 HumanGPT is an iPhone app that rewrites AI drafts so they sound like you and shows an AI-likeness estimate for every sentence. Here's how the two compare on features, prices and privacy.
The short verdict
GPTZero checks whether a text looks AI-written. HumanGPT rewrites your draft and adds an AI-likeness estimate as a check.
Choose HumanGPT if…
- You want an AI draft rewritten in a tone you pick, or in your own voice on Pro.
- Facts, numbers and citations have to survive the rewrite.
- You write on an iPhone and import from photos, scans, Google Docs or web links.
HumanGPT vs GPTZero at a glance
Each small number links to a source at the end of the page.
| Feature | HumanGPT | GPTZero |
|---|---|---|
| Platforms | iPhone app (iOS 17 or later). Web editor planned, not live yet. | Web dashboard, API, Chrome extension (Origin), and Google Docs, Classroom, Canvas and Zapier integrations.134 |
| Free plan | Yes 1 free demo rewrite, then 300 words a day, up to 300 words per rewrite. | Yes 10,000 words a month, Basic AI Scan, 1 Advanced Scan.3 |
| Paid pricing | Pro: $5.99 a week with a 3-day free trial, or $39.99 a year (US prices).10 | Premium from €18.99 a month, or €9.99 a month billed annually (as shown in Germany).3 |
| Word limits | Free: 300 words a day. Pro: 50,000 words a week (fair use), up to 3,000 words per rewrite. | Scans: 10,000 words a month free, 300,000 on Premium, 500,000 on Professional.3 |
| Rewriting approach | Anthropic Claude models and the open-source humanizer skill (26 patterns from Wikipedia's "Signs of AI writing"). Tones, strength, text types; voice matching and sentence rewrite on Pro. | We didn't find a humanizer among its products. Its Grammar Checker suggests edits.15 |
| AI-likeness or detection | Yes AI-likeness estimate with per-sentence highlights. An estimate, not proof. | Yes Document, sentence and word-level results, confidence scores, "AI vocabulary" and sentence highlights. Basic and Advanced scans.34 |
| Facts and citations kept | Yes Integrity check for facts, numbers and citations, plus a fact-check pass when needed. | Its Hallucination Detector flags made-up citations and poorly supported claims.6 |
| Document import and export | Import .txt, photos and scans (on-device OCR), Google Docs and web links; PDF and Word on Pro. Export .txt, .docx, .pdf. | Paste or upload .docx, .pdf and image files, up to 50 at a time (250 on Professional, per the pricing page). AI reports on Premium.37 |
| Languages | App in English, German, Spanish and French. | Detection in English, German, Portuguese, French and Spanish.1 |
| Privacy and data retention | Processed in the EU (Firebase europe-west1) and by Replicate (Anthropic Claude) only to produce results. Results kept 30 days; uploads deleted after extraction. No ads.11 | GPTZero Inc. (New York, US). Dashboard scans are stored and used in aggregate to improve the service; API documents aren't. Personal data kept no longer than 3 months after an account closes, unless the law requires longer.48 |
| Notable claims | Doesn't promise undetectable text or a pass on any detector or exam. | Advertises "99% Accuracy". Its homepage FAQ adds: "No AI detector is 100% accurate." We haven't tested the accuracy claim.1 |
- Yes listed by the provider
- Partly some of it, or only on some plans
- No the provider says it isn't offered
- Not stated not in the sources we checked
Where GPTZero is stronger
For these jobs, GPTZero is the better fit:
-
It works where schools already are
GPTZero runs in the browser and connects to Google Docs, Google Classroom, Canvas and Zapier. Its homepage lists SOC 2 Type II and FERPA, GDPR and CCPA compliance.1 HumanGPT is an iPhone app, and its web editor isn't live yet.
-
A record of how a text was written
With the Chrome extension, Writing Replay plays back how a Google Doc was written.2 A student who worries about a false flag can share that record. HumanGPT's AI-likeness estimate can't prove who wrote a text.
-
More checks, bigger batches
GPTZero also has a plagiarism check, Expert Feedback and a Hallucination Detector for made-up citations.16 Professional scans up to 250 files at once.3 HumanGPT's fact checks cover whether your own facts survive a rewrite.
Where HumanGPT is different
GPTZero's sources don't describe these, or describe them differently.
-
It rewrites the draft for you
Pick a tone (natural, casual, professional, academic or friendly), a strength and a text type. On Pro, voice matching follows a sample of your writing, and you can rewrite single sentences the estimate marks.
-
Your facts get checked
Each rewrite gets an integrity check for changed or missing facts, numbers and citations. When your text has numbers, names or citations, or something looks changed, a fact-check pass compares the rewrite with your original and fixes what it finds; anything still missing is flagged.
-
Short retention, EU backend
Text goes to our EU backend and to Replicate (Anthropic Claude) only to produce the result. Result copies are deleted after 30 days, uploads once their text is extracted.
How rewriting and detection differ
HumanGPT sends your draft to Anthropic Claude models with instructions from the open-source humanizer skill, which covers 26 patterns from Wikipedia's "Signs of AI writing".1213 You set the tone and strength, and the app checks that your facts and citations made it through.
GPTZero's Grammar Checker suggests edits you accept or reject, which GPTZero says help you "rephrase and rewrite your sentences for better readability and fluency".5 A May 13, 2026 GPTZero article, "What 'Humanize' Actually Means (and Why It Won't Help Your Writing)", argues against humanizer tools.9
Example rewrite
Tone: naturalSleep helps the brain store new memories. Participants who slept eight hours recalled 23% more word pairs (Okafor, 2023).
Fixed
- Overused AI words
- Avoiding is, are, has
- Shallow -ing rider
Kept
- eight hours
- 23% more
- (Okafor, 2023)
Sample text and rewrite written for this page to show typical edits. Results depend on your text and settings. We don't show GPTZero scores, because one sample can't fairly represent another tool.
Pricing compared
GPTZero bills monthly or annually, by words scanned per month.3 HumanGPT Pro is weekly or yearly.
HumanGPT
- Free
- $01 free demo rewrite, then 300 words a day, up to 300 per rewrite
- Pro weekly
- $5.99 / week3-day free trial. 50,000 words a week (fair use), up to 3,000 per rewrite
- Pro yearly
- $39.99 / yearSame Pro limits
US prices.10
GPTZero
- Free
- €010,000 words a month, Basic AI Scan
- Premium
- €18.99 / monthor €9.99 a month billed annually. 300,000 words a month
- Professional
- €35.99 / monthor €19.99 a month billed annually. 500,000 words a month
Teams buy seats or contact sales.3
HumanGPT prices are US prices; GPTZero's are in euros as shown in Germany on October 8, 2026. Prices vary by country, and either provider can change them at any time.
Questions about HumanGPT and GPTZero
Is HumanGPT an alternative to GPTZero?
Only if you need rewriting. GPTZero is an AI detector with extras such as Writing Replay. HumanGPT is an iPhone app that rewrites AI drafts, keeps facts and citations and shows an AI-likeness estimate. To check other people's writing, GPTZero is the closer fit.
Can HumanGPT promise an AI detector won't flag my text?
No. No tool can promise how a detector, a teacher or an editor will judge a text, and HumanGPT doesn't try to. It rewrites your draft so it reads naturally and shows an AI-likeness estimate, which is an estimate and not a verdict. Follow the rules of your school or workplace.
Does GPTZero have a humanizer?
We didn't find one among GPTZero's products. Its Grammar Checker suggests edits, and a May 2026 GPTZero article argues that humanizing won't help your writing. HumanGPT is built for rewriting, with tone, strength and, on Pro, voice matching.
Is GPTZero free, and how much does it cost compared with HumanGPT?
GPTZero's free plan scans 10,000 words a month. Premium costs €18.99 a month, or €9.99 a month billed annually, as shown in Germany. HumanGPT is free for 300 words a day, and Pro costs $5.99 a week with a 3-day free trial or $39.99 a year in the US. Prices change, so check both before you buy.
Sources
All sources were last checked in October 2026.
- GPTZero home page (opens in a new tab)
- GPTZero Authorship and Writing Replay (opens in a new tab)
- GPTZero pricing (opens in a new tab)
- GPTZero FAQ (opens in a new tab)
- GPTZero Grammar Checker (opens in a new tab)
- GPTZero Hallucination Detector (opens in a new tab)
- GPTZero technology (opens in a new tab)
- GPTZero privacy policy (last updated April 2, 2026) (opens in a new tab)
- GPTZero article: What "Humanize" Actually Means (May 13, 2026) (opens in a new tab)
- HumanGPT pricing
- HumanGPT privacy policy
- humanizer, an open-source skill by Siqi Chen (MIT License) (opens in a new tab)
- Wikipedia: Signs of AI writing (opens in a new tab)
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- HumanGPT vs ZeroGPT AI detector with writing tools
- HumanGPT vs Undetectable AI Humanizer suite with a detector
- HumanGPT vs StealthGPT Humanizer, detector and essay writer
- HumanGPT vs WriteHuman AI humanizer and detector
- HumanGPT vs Walter Writes AI AI humanizer with a detector
- HumanGPT vs BypassGPT Web humanizer with an AI checker
- HumanGPT vs Clever AI Humanizer Free web humanizer
- HumanGPT vs QuillBot Writing suite with a humanizer
- HumanGPT vs Grammarly Writing assistant with a humanizer
- All HumanGPT comparisons Overview of all 10 tools
Try HumanGPT on your next draft
Paste a paragraph, pick a tone and check the AI-likeness estimate. Your first rewrite is free.
For iPhone with iOS 17 or later.