Best for
Best for people and teams who write German professionally and want the Duden as the authority on every correction.
- Freelancers
- Small and mid-sized
- Enterprise
Writing Assistance & Style Comparison
Duden-Mentor vs. Grammarly
At a glance
At a glance
Best for
Best for individuals and teams who want grammar, clarity and tone help across every app they write in.
- Freelancers
- Small and mid-sized
- Enterprise
Cataleo does not name a winner. Both statements come from the vendors themselves.
Full Comparison
| Criterion | Duden-Mentor | Grammarly |
|---|---|---|
| Starting price | Not stated | Free tier; Pro from $12 / user / month $12 per member per month billed annually, $30 billed monthly. Enterprise is custom. |
| Free trial | Free version for short checks; the Word add-in can be tested free without payment details | Free tier with 100 AI prompts per month |
| Commercial use | Not stated | Yes |
| Output | Corrections and style notes on German text, plus AI rewrites and improvement suggestions | Grammar, clarity and tone suggestions, plus generative AI drafts |
| Hosting | Cloud; texts are sent to a server on AWS in Frankfurt, Germany | Not stated |
| Made in | Germany | Not stated |
| What it works on | German text pasted into the web app, text in browser-based applications through the extensions, and .docx documents in Microsoft Word | Emails, documents, business and academic writing |
| Checks covered | Spelling, grammar, punctuation and style, flagging filler words, repetitions, redundancies, overly long sentences and complex sentence structures, with synonym suggestions | Spelling, grammar and punctuation corrections and tone detection on the free plan. Pro adds full-sentence rewrites, fluency, inclusive language, citation consistency, AI-text detection and plagiarism detection |
| Style guide and tone | Selectable correction styles, a personal dictionary for foreign, technical and company-specific words, and spelling variants for Germany, Austria and Switzerland | Yes, brand tone and style guide (unlimited on Enterprise) |
| Scores and reports | Not stated | Yes, writing performance score and tone detection |
| AI rewriting | An AI assistant rewrites text or generates improvement suggestions: 250 uses a month on Premium, unlimited on Premium Plus | Yes, generative AI prompts, rewrites and tone adjustments |
| Languages | German only, with spelling variants for Germany, Austria and Switzerland | English with American, British, Canadian, Australian and Indian spelling and grammar, plus spelling and basic grammar in more than 20 further languages. Advanced suggestions and paragraph rewrites cover Spanish, French, German, Portuguese and Italian, and paid plans translate into 19 languages |
| Where it runs | Web app at mentor.duden.de, browser extensions for Chrome, Firefox and Edge, and a Word add-in for Microsoft 365 on Windows and Mac, Word 2019, Word 2016 for Mac and Word online; an internet connection is required | Browser extensions for Chrome, Safari, Firefox and Edge, desktop apps for Windows 10 or newer and macOS 11 or newer that also reach Word, Outlook, PowerPoint and Teams, and mobile apps for iOS 17 and Android 9 or newer |
| Privacy and data handling | Texts are sent encrypted and deleted immediately after the check; text given to the AI assistant is passed to Telekom Deutschland and/or Microsoft, and in the free version AI-corrected texts are kept for up to four weeks for quality assurance | Content is not sold or used for advertising, and is stored on AWS in US data centres, encrypted in transit and at rest. A Product Improvement and Training control is on by default for individuals and can be switched off; on team accounts only admins change it. SOC 2 Type 2 and ISO 27001 certified, and Enterprise adds confidential mode, data loss prevention and its own encryption keys |
| Teams and sharing | Company licences per user, assigned and withdrawn in a licence management area, sold as annual licences with volume discounts and payable by invoice | Yes, team analytics, snippets and shared style guide |
| API | An API for integrating the checker into company systems | No public API; the Text Editor SDK for developers was discontinued in 2024 |
| AI features | Yes | Yes |
| Deployment | Cloud (SaaS), Browser-based | Cloud (SaaS), Browser-based |
| Support | more entries Email helpdesk, Phone | Email helpdesk |
| Onboarding | Not stated | Documentation and knowledge base |
| Company size | Freelancers, Small and mid-sized, Enterprise | Freelancers, Small and mid-sized, Enterprise |
| Integrations | Microsoft Word, Google Chrome, Mozilla Firefox, Microsoft Edge | more entries Gmail, Google Docs, Microsoft Word, Salesforce, Zendesk, Jira, LinkedIn, X, Facebook, Instagram, YouTube, Medium, Google Chrome, Safari, Firefox, Microsoft Edge |
Add a tool
Adds a column to the table, from the tools in this category.
Row where the values differ The small markers point at the lower number, the longer list or the stated feature. They describe the data, they are not a verdict.
The short version
Key Differences
- Free trial Duden-Mentor Free version for short checks; the Word add-in can be tested free without payment details Grammarly Free tier with 100 AI prompts per month
- Support Duden-Mentor Email helpdesk, Phone Grammarly Email helpdesk
- Output Duden-Mentor Corrections and style notes on German text, plus AI rewrites and improvement suggestions Grammarly Grammar, clarity and tone suggestions, plus generative AI drafts
- What it works on Duden-Mentor German text pasted into the web app, text in browser-based applications through the extensions, and .docx documents in Microsoft Word Grammarly Emails, documents, business and academic writing
- Checks covered Duden-Mentor Spelling, grammar, punctuation and style, flagging filler words, repetitions, redundancies, overly long sentences and complex sentence structures, with synonym suggestions Grammarly Spelling, grammar and punctuation corrections and tone detection on the free plan. Pro adds full-sentence rewrites, fluency, inclusive language, citation consistency, AI-text detection and plagiarism detection
Every line is one datapoint from the table above, picked automatically. Nothing here is written text.
The trade-offs
Strengths and Limitations
Duden-Mentor
Strengths
- Checks against the Duden, the reference for German spelling
- Handles German, Austrian and Swiss spelling conventions
- Checks up to 100,000 characters at once on Premium and 200,000 on Premium Plus
- Company licences come with licence management and invoice payment
Limitations
- Checks German text only
- The Word add-in and browser extensions need a paid plan
- The Word add-in reads .docx files only, not .doc or .odt
- Every check needs an internet connection
Grammarly
Strengths
- Free tier is genuinely useful for everyday writing
- Works across apps and browsers through extensions
- Brand tones and style guides keep a consistent voice
Limitations
- Generative AI is capped by monthly prompt limits
- Enterprise pricing is custom, not published
Plans
Pricing
Duden-Mentor
- Premium Not stated Up to 100,000 characters per check, 250 AI text optimisations a month, browser and Word extensions; terms of one, three or twelve months.
- Premium Plus Not stated Up to 200,000 characters per check and unlimited AI text optimisations.
- Company licences Not stated Annual per-user licences, cheaper per licence as the number grows; more than 25 licences quoted on request.
Grammarly
- Free $0 100 AI prompts per month, mistake-free writing and tone detection.
- Pro $12 Per member per month billed annually. $30 billed monthly. 2,000 AI prompts per month, full-sentence rewrites, tone adjustment and brand consistency.
- Enterprise Custom Contact sales. Unlimited members and unlimited generative AI prompts, plus confidential mode, granular roles and permissions, data loss prevention and dedicated support.
What users say
Review Scores · opens after launch
Duden-Mentor
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Nothing has been published here yet, and no score is shown. How a review is checked before it appears is described below.
Grammarly
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Nothing has been published here yet, and no score is shown. How a review is checked before it appears is described below.
How we check reviews
Reviews are not published yet. The form on a tool's page works and reaches us, but nothing from it appears on this site, so no score here is based on a review. The rules below are the ones that will apply once reviews go live.
Every review is read by a person before it appears. We require a working email address and use it to come back to the author, so a review has a reachable sender rather than being anonymous. We publish positive and negative reviews alike, we pay nothing and offer nothing for a review, and we accept none that was bought or incentivised.
What we cannot do is verify a purchase. There is no shop here and no account, so whether the author really used the tool rests on what they tell us, plus the plausibility of what they write. We say so rather than implying a check that does not exist.
A vendor cannot have a review removed, cannot buy one, and cannot have one changed. Paid placement and a paid listing have no effect on which reviews appear or on any score.
Where this comes from
Where this comes from
Duden-Mentor https://mentor.duden.de · checked against the official source on 2026-10-10
Grammarly https://www.grammarly.com · checked against the official source on 2026-10-10
This table lists factual criteria taken from information the vendors publish themselves. For how we put it together, see the methodology.