AI draft
Hi Sam, I hope this email finds you well. I'm reaching out to share a comprehensive Q3 budget update. Additionally, travel costs came in at $18,400, which represents a 12% reduction compared to Q2.
HumanGPT vs Grammarly: AI humanizer, pricing and platforms compared
Grammarly is a writing assistant for spelling, grammar and tone,1 and its website has a free AI Humanizer that rewrites AI text "to improve clarity, flow, and readability".2 HumanGPT is an iPhone app built for that one job, and it checks facts, numbers and citations after each rewrite. Every claim about Grammarly below is sourced.
The short verdict
Grammarly helps across your computer, browser and phone. HumanGPT humanizes AI drafts on iPhone.
Choose HumanGPT if…
- You want facts, numbers and citations checked after every rewrite.
- You start from a photo, scan, web link or PDF (Pro).
- You want sentences that still read like AI highlighted, and rewritten one at a time on Pro.
HumanGPT vs Grammarly at a glance
Numbers link to the sources below.
| Feature | HumanGPT | Grammarly |
|---|---|---|
| Platforms | iPhone app (iOS 17 or later). A web editor is planned but not live yet. | Windows, Mac, Android, four browser extensions, Microsoft Office, Google Docs.4 iPhone and iPad (iOS 17.4 or later) and Apple Vision.3 |
| Free plan | Yes 1 free demo rewrite, then 300 words a day, up to 300 words per rewrite. | Yes Spelling, grammar, tone detection, 100 AI prompts a month.1 Free web AI Humanizer and AI Detector.26 |
| Paid pricing | Pro: $5.99 a week with a 3-day free trial, or $39.99 a year (US prices).11 | Web Pro: €12, 7-day free trial, billing period not shown (as shown in Spain).1 iPhone: $29.99 a month, $59.99 a quarter or $139.99 a year; the App Store also lists Mobile Only plans at $17.99 a month and $83.99 or $119.99 a year (US).3 |
| Word limits | Free: 300 words a day. Pro: 50,000 words a week (fair use), up to 3,000 words per rewrite. | Not stated No humanizer word limits published.2 AI prompts: 100 a month on Free, 2,000 on Pro.1 |
| Rewriting approach | Anthropic Claude models guided by 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. | Scans for AI-typical patterns, then rephrases. Free accounts get a Humanizer agent with preset and custom voices.2 |
| AI-likeness or detection | Yes Built-in AI-likeness estimate with per-sentence highlights. An estimate, not proof of authorship. | Yes Free web detector: share of text that "appears to be AI-generated". Pro's AI Detector agent points to specific parts.6 |
| Facts and citations kept | Yes Integrity check for facts, numbers and citations, plus a fact-check pass when needed. | Not stated Says meaning and accuracy are kept; no separate fact check described.2 |
| 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. | Editor: .doc, .docx, .odt, .txt, .rtf up to 4 MB; PDF not supported.7 Web humanizer: "Upload file" button.2 |
| Languages | App in English, German, Spanish and French. | Spelling and grammar in 20+ languages.8 Humanizer agent in 6.2 iPhone app in 6.3 |
| 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.12 | Says it doesn't sell or monetize user content; you can opt out of AI training.9 Uses collected data to train its AI models, kept "as long as necessary to provide our products".10 |
| Notable claims | Doesn't promise undetectable text or a pass on any detector or exam. | Says its humanizer "is not intended to bypass AI detectors".2 Claims "99% detection accuracy" on RAID's benchmark. We haven't tested this.6 |
- 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 Grammarly is stronger
-
It runs on the devices you already use
Grammarly works on Windows, Mac and Android, in four browsers, and in Microsoft Office and Google Docs.4 Its iOS app also runs on iPad and Apple Vision.3 HumanGPT is iPhone-only for now.
-
Authorship shows how you wrote
On Free and Pro, Authorship tracks your writing in Google Docs, Word or the Grammarly Editor, shows whether text was typed, pasted from a website, AI-generated or a Grammarly suggestion, and can replay the process. You choose who sees it.5 HumanGPT has no equivalent.
-
Voices and languages for free
A free account adds the Humanizer agent: four preset voices, a custom voice from your own writing sample, and six languages, including Italian and Portuguese.2 In HumanGPT, voice matching is Pro.
-
A full writing assistant
Spelling and grammar checks cover 20+ languages,8 Pro adds plagiarism detection,1 and the iPhone keyboard takes voice dictation.3
Where HumanGPT is different
-
Facts get their own check
After each rewrite, HumanGPT runs an integrity check on facts, numbers and citations, then a fact-check pass when needed. Grammarly's humanizer page doesn't describe a separate check.2
-
Highlights for each sentence
The AI-likeness estimate highlights each sentence that still reads like AI, and Pro rewrites just those sentences. Grammarly's free detector gives an overall percentage; its AI Detector agent, which points to specific parts, is on Pro.6
-
PDFs, photos and web links
Import PDF and Word (Pro), .txt, photos and scans (on-device OCR), Google Docs or web links, and export to .txt, .docx or .pdf. Grammarly says its Editor doesn't support PDF.7
How the rewriting differs
HumanGPT runs on Anthropic Claude models, guided by the open-source humanizer skill and its 26 patterns from Wikipedia's "Signs of AI writing".1314 You set a tone (natural, casual, professional, academic or friendly), a strength and a text type.
Grammarly says its humanizer finds AI-typical patterns, such as an overly formal tone or repetitive phrasing, and rephrases them without changing the meaning.2
Example rewrite
Tone: professionalHi Sam, here's the Q3 budget update. Travel costs came in at $18,400, 12% less than in Q2.
Fixed
- Staged run-up
- Overused AI words
- Avoiding is/are/has
Kept
- $18,400
- 12% vs Q2
Sample text and rewrite written for this page to show typical edits. Results depend on your text and settings. We don't show Grammarly output, because one sample can't fairly represent another tool.
Pricing compared
Grammarly Pro covers its whole writing assistant, so the prices aren't like for like.1
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.11
Grammarly
- Free
- €0 / month100 AI prompts a month; free web humanizer and detector
- Pro, iPhone
- $29.99 / monthOr $59.99 a quarter, or $139.99 a year
- Mobile Only, iPhone
- $17.99 / monthOr $83.99 or $119.99 a year
- Pro, web
- €127-day free trial; billing period not shown
Prices as listed in October 2026, before tax: US prices in dollars, Grammarly's web price in euros as shown in Spain. Either provider can change them.
Questions about HumanGPT and Grammarly
Is HumanGPT an alternative to Grammarly?
For humanizing AI drafts on an iPhone, it can be, and HumanGPT also checks facts, numbers and citations. For grammar help across your devices, or Authorship, Grammarly covers more.
Is Grammarly's humanizer free, and what does Pro cost?
The web AI Humanizer is free, and a free account adds the Humanizer agent. In the US App Store, Grammarly Pro is $29.99 a month or $139.99 a year, with Mobile Only plans from $17.99 a month. HumanGPT Pro is $5.99 a week or $39.99 a year (US prices). Prices change, so check both before you buy.
Can HumanGPT promise my text won't be flagged as AI?
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 Grammarly use my writing to train its AI?
Grammarly's privacy policy says it uses collected information to train its AI models, and its Trust Center says you can opt out in the "Product Improvement and Training" setting. HumanGPT processes your text only to produce your result, as its privacy policy explains.
Sources
All sources were last checked in October 2026.
- Grammarly plans and pricing (opens in a new tab)
- Grammarly AI Humanizer and FAQ (opens in a new tab)
- Grammarly: AI Keyboard & Voice on the App Store (US) (opens in a new tab)
- Grammarly home page: "Get Grammarly" list of apps and extensions (opens in a new tab)
- Grammarly Authorship (opens in a new tab)
- Grammarly AI Detector and FAQ (opens in a new tab)
- Grammarly Support: What are the limitations when using Grammarly? (opens in a new tab)
- Grammarly supported languages (opens in a new tab)
- Grammarly Trust Center (opens in a new tab)
- Superhuman (formerly Grammarly) Privacy Policy, effective July 6, 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)
Other comparisons
- HumanGPT vs ZeroGPT AI detector with writing tools
- HumanGPT vs GPTZero AI detector for educators
- 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
- 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.