Skip to content
SPECIFICTION
Get listed

Duden-Mentor

mentor.duden.de

From €2.99/mo Free plan WebWindowsmacOSAPIBrowser extension
Visit mentor.duden.de
Spec score 9.4 #1 of 88 in Grammar checkers

What it is

Duden-Mentor checks German text for spelling, grammar, punctuation, and style, then suggests corrections. It can flag filler words, repeated wording, and overly long sentences, with suggestions for readability. The service supports German variants for Germany, Austria, and Switzerland, but checks German only. Browser extensions are available for Chrome, Firefox, and Microsoft Edge, and the plug-in works in text fields on services including Gmail, Web.de, GMX.de, Trello, Facebook, and WordPress. A Microsoft Word add-in supports macOS from Word 2016 and Windows from Word 2019. An internet connection is required. Duden says text is encrypted in transit, not used for AI training, and deleted after checking. Basis is free and lists a 10-word personal dictionary and 500 characters without an account. Pur costs €2.99 a month, billed 35,88 € pro Jahr, with 10 test corrections or rewrites monthly. Premium costs €7.95 a month, billed 95,40 € pro Jahr, with 250 monthly text optimizations; Premium Plus costs €9.95 a month, billed 119,40 € pro Jahr, with unlimited optimizations. Paid plans are annually payable and annually cancellable.

Spec sheet

What it does
Duden-Mentor is an online German writing assistant for spelling, grammar, punctuation and expression.Read 20 Oct 2026 · mentor.duden.de
Purpose
Duden-Mentor checks German text for spelling, grammar, punctuation and style and suggests corrections.Read 11 Oct 2026 · lp.mentor.duden.de
Free plan
YesRead 20 Sep 2026 · mentor.duden.de
Integrations
The Word add-in supports Microsoft Word for macOS from version 2016 and Windows from version 2019.Read 11 Oct 2026 · mentor.duden.de
Security
The maker says texts are transmitted encrypted, are not used for AI training, and are deleted after checking.Read 11 Oct 2026 · duden.de
Support
The FAQ says Duden customer service can provide personal help if its answers do not resolve a question.Read 11 Oct 2026 · duden.de
Founded
Cornelsen states that Franz Cornelsen founded the Cornelsen Verlag in Berlin in 1946.Read 20 Oct 2026 · cornelsen.de
Maker
Duden is a brand of the Cornelsen Group.Read 11 Oct 2026 · duden.de
API authentication
API access uses an x-api-key header and developers request keys by emailing Duden.Read 20 Oct 2026 · api.duden.io
API delivery
API v2 returns a correlation ID immediately and posts the processed result to a publicly reachable HTTPS callback URL.Read 20 Oct 2026 · api.duden.io
API language options
API v2 accepts german_DE, german_AT and german_CH variants and supports complete-result or sentence-segment callbacks.Read 20 Oct 2026 · api.duden.io
API versions
The public correction API provides v1 for spellchecking and synonyms and v2 for asynchronous AI correction and paraphrasing.Read 20 Oct 2026 · api.duden.io
Browser extension
YesRead 20 Sep 2026 · mentor.duden.de
Browser integrations
Extensions work in Chrome, Firefox and Edge and can insert corrected text into services such as Gmail, WordPress, Trello, Facebook and Twitter.Read 20 Oct 2026 · mentor.duden.de
Browser support
Browser extensions are available for Chrome, Firefox and Microsoft Edge.Read 11 Oct 2026 · mentor.duden.de
Business licensing
Business plans use annual per-user licenses, and prices for more than 25 licenses are available on request.Read 11 Oct 2026 · lp.mentor.duden.de
Company relationship
Duden is a brand of Cornelsen Group and the Duden-Mentor Word add-in is supplied by Cornelsen Verlag GmbH.Read 20 Oct 2026 · linkedin.com
Company size
LinkedIn lists Duden in the 11–50 employee range and places its headquarters in Berlin.Read 20 Oct 2026 · linkedin.com
Data hosting
The business product page states that texts are sent using TLS 1.2 and a 128-bit key to AWS servers contractually located in Frankfurt, Germany.Read 11 Oct 2026 · lp.mentor.duden.de
Desktop app
NoRead 20 Sep 2026 · mentor.duden.de
Grammar
It checks German grammar and displays correction suggestions beneath the text.Read 20 Oct 2026 · mentor.duden.de
Languages
The service checks German texts only.Read 11 Oct 2026 · lp.mentor.duden.de
Licence
The Firefox extension is marked All Rights Reserved, so the product is proprietary rather than open source.Read 20 Oct 2026 · addons.mozilla.org
Limit: comma accuracy
An independent test reports that the tool sometimes removes useful commas or inserts commas in unsuitable positions.Read 20 Oct 2026 · dkeu.de
Limit: document workflow
An academic-focused review says the web editor has no file upload, loses formatting and footnotes when copying from Word, and requires corrections to be accepted individually.Read 20 Oct 2026 · campuslektor.com
Limit: pricing and contracts
Trustpilot reviewers complain that advertised monthly prices can result in annual contracts and that the service is expensive compared with alternatives.Read 20 Oct 2026 · de.trustpilot.com
Limit: reliability
Independent reports mention disappearing text, maintenance downtime and browser-extension sessions repeatedly logging users out.Read 20 Oct 2026 · dkeu.de
Limit: style overmarking
A professional reviewer found that many style warnings in a scientific essay targeted word repetition and made the text difficult to assess.Read 20 Oct 2026 · christianwoellecke.de
Mobile app
NoRead 20 Sep 2026 · mentor.duden.de
Notable company news
Cornelsen says the Bibliographisches Institut and Cornelsen merged in 2022, bringing Duden language technology into the combined company.Read 20 Oct 2026 · cornelsen.de
Online integrations
The browser plug-in works in text fields on services including Gmail, Web.de, GMX.de, Trello, Facebook and WordPress.Read 11 Oct 2026 · mentor.duden.de
Praise: Duden reference
Independent reviewers describe the Duden dictionary and brand as the product's main credibility advantage.Read 20 Oct 2026 · campuslektor.com
Praise: spelling detection
Independent testers report that Duden-Mentor quickly catches obvious spelling mistakes and typos.Read 20 Oct 2026 · dkeu.de
Punctuation
The checker analyzes punctuation, including comma placement and sentence-ending marks.Read 20 Oct 2026 · mentor.duden.de
Rating on Chrome Web Store
3.3 out of 5 from 75 ratingsRead 20 Oct 2026 · chromewebstore.google.com
Rating on Firefox Add-ons
4 out of 5 from 51 reviewsRead 20 Oct 2026 · addons.mozilla.org
Rating on Microsoft Marketplace
2.2 out of 5 from 74 reviewsRead 20 Oct 2026 · marketplace.microsoft.com
Rating on Trustpilot
1.5 out of 5 from 45 reviews for the Duden profileRead 20 Oct 2026 · de.trustpilot.com
Regional German
The product supports German variants for Germany, Austria and Switzerland.Read 20 Oct 2026 · mentor.duden.de
Security claim
Duden says submitted texts are encrypted in transit, anonymized for data protection and excluded from AI training.Read 20 Oct 2026 · mentor.duden.de
Spelling
The service detects misspellings and proposes corrected forms using vocabulary from Duden works.Read 20 Oct 2026 · mentor.duden.de
Style analysis
Premium checks filler words, word repetitions, colloquial wording and other style issues.Read 20 Oct 2026 · mentor.duden.de
Style suggestions
YesRead 20 Sep 2026 · mentor.duden.de
Synonyms
A built-in thesaurus offers meaning-grouped synonyms and can replace repeated words.Read 20 Oct 2026 · mentor.duden.de
Text capacity
Depending on the package, one check can process up to 200,000 characters; Premium handles 100,000 and Premium Plus 200,000 in Word.Read 20 Oct 2026 · mentor.duden.de
Text retention
The Word-add-in privacy notice says texts sent for checking are used only for that check and deleted immediately afterward.Read 20 Oct 2026 · mentor.duden.de
Usage requirement
The service requires an internet connection.Read 11 Oct 2026 · lp.mentor.duden.de
Word features
The Word add-in marks issues in documents, accepts or rejects suggestions, detects long sentences and proposes dictionary additions for unknown names.Read 20 Oct 2026 · mentor.duden.de
Word support
The Word add-in supports Word 2016 or later on macOS, Word 2016 or later on Windows and Word on the web.Read 20 Oct 2026 · store.office.com
Writing suggestions
It identifies filler words, repeated words and overly long sentences and offers ways to improve style and readability.Read 11 Oct 2026 · duden.de

Plans and prices

Basis Free 10 Wörter im persönlichen Wörterbuch · 500 Zeichen ohne Benutzerkonto Read 11 Oct 2026 · lp.mentor.duden.de
Basis Free 0 € / Monat basic functions · personal bookmark with registration Read 20 Oct 2026 · mentor.duden.de
Duden Pur €2.99 a month 35,88 € per year, annual payment and annual cancellation ad- and tracking-free duden.de and app · personal bookmark Read 20 Oct 2026 · mentor.duden.de
Pur €2.99 a month 35,88 € pro Jahr; jährliche Zahlweise, jährlich kündbar 10 Test-Korrekturen/Umformulierungen pro Monat Read 11 Oct 2026 · duden.de
Premium €7.95 a month 95,40 € pro Jahr; jährliche Zahlung, jährlich kündbar 250 Textoptimierungen pro Monat · Browser-Erweiterung · Word-Add-in · persönliches Wörterbuch unbegrenzt Read 11 Oct 2026 · duden.de
Premium €7.95 a month 95,40 € per year, annual payment and annual cancellation 250 text optimizations per month · selectable text type and style · Word add-in · Chrome, Firefox and Edge extensions · style tips · synonyms Read 20 Oct 2026 · mentor.duden.de
Premium Plus €9.95 a month 119,40 € per year, annual payment and annual cancellation unlimited text optimizations per month · selectable text type and style · Word add-in · Chrome, Firefox and Edge extensions · style tips · synonyms Read 20 Oct 2026 · mentor.duden.de
Premium Plus €9.95 a month 119,40 € pro Jahr; jährliche Zahlung, jährlich kündbar Unbegrenzte Textoptimierungen pro Monat · Browser-Erweiterung · Word-Add-in · persönliches Wörterbuch unbegrenzt Read 11 Oct 2026 · duden.de

Every Duden-Mentor plan and price →

Strong points and limits

Strong points

  • Checks spelling, grammar, punctuation, and style.
  • Supports German variants for Germany, Austria, and Switzerland.
  • Extensions support Chrome, Firefox, and Microsoft Edge.
  • Duden says checked text is deleted afterward.

Limits

  • Checks German only.
  • Requires an internet connection.
  • Basis limits use to 500 characters without an account.
  • Paid plans are annually payable.

Who it suits

Duden-Mentor suits people writing German who want spelling, grammar, punctuation, and style suggestions in browser text fields or supported versions of Word. It also offers regional variants for writers using German in Germany, Austria, or Switzerland.

Duden-Mentor in depth

Read the full write-up

Duden-Mentor is a German-only writing checker for people who want more than spelling fixes, especially those working in browsers or Microsoft Word. Its strongest case is focused help with German correctness and readability; annual billing, usage quotas and narrow language coverage make it less suitable for multilingual or offline work.

Overview

The service checks spelling, grammar and punctuation, then adds style guidance for filler words, repeated words and overly long sentences. That makes it useful both for correcting mistakes and for tightening prose before publication. Regional support for Germany, Austria and Switzerland is a practical advantage when wording must match a particular German-speaking audience. Duden-Mentor checks German only, so it cannot replace a multilingual writing assistant.

Key features

Extensions for Chrome, Firefox and Microsoft Edge put corrections into text fields on services including Gmail, Web.de, GMX.de, Trello, Facebook and WordPress. For people who compose directly in web apps, this is more convenient than copying text into a separate checker. The Word add-in supports Microsoft Word for macOS from version 2016 and Windows from version 2019, giving subscribers a familiar desktop workflow without a separate desktop application. Compatibility is tied to those versions, so users on older or different releases should not assume the add-in will work.

The style layer is more consequential than a basic spellchecker: identifying repetition, padding and sentence length can help make routine business or editorial text clearer. The trade-off is that every check requires an internet connection, ruling out disconnected editing. Duden says text is encrypted in transit, not used for AI training and deleted after checking. Its business product page describes TLS 1.2 transmission with a 128-bit key to AWS servers contractually located in Frankfurt, Germany. Duden customer service can provide personal assistance when the FAQ does not resolve a question.

Pricing

The free Basis plan costs nothing. It allows 10 words in a personal dictionary and checks up to 500 characters without an account. That is enough for occasional short snippets, but the character ceiling makes it unsuitable for sustained document work.

Pur costs €2.99 a month, billed as 35,88 € per year with annual payment and annual cancellation. It includes 10 test corrections or reformulations per month. This is the low-cost choice for light users who want more than the free limit, but the monthly allowance will constrain regular editing.

Premium costs €7.95 a month, billed as 95,40 € per year; payment is annual and cancellable yearly. It provides 250 text optimizations per month, the browser extension, Word add-in and an unlimited personal dictionary. It fits frequent writers who can forecast their usage. Premium Plus costs €9.95 a month, billed as 119,40 € per year on the same annual terms, and removes the optimization quota with unlimited monthly text optimizations while retaining the extensions, add-in and unlimited dictionary. It is the sensible tier for heavy or unpredictable workloads.

Business plans use annual per-user licenses; prices for more than 25 licenses are available on request.

Platforms

Duden-Mentor is offered through the web and browser extensions, with Word integration on supported macOS and Windows versions. There is no desktop or mobile app, and internet access is required. The platform mix suits browser-first and Word-based writing, not offline or phone-centered editing.

Who it's for

Choose it for German writing in email, web services or supported Word versions when regional language choices and style cleanup matter. It is particularly appropriate for individuals who can work within monthly optimization quotas, or for organizations willing to manage annual per-user licenses. Look elsewhere if you need multiple languages, offline operation, a mobile app or a standalone desktop editor.

Pros and cons

Pros

Combines German spelling, grammar and punctuation checks with targeted style suggestions for filler, repetition and long sentences.

Supports Germany, Austria and Switzerland variants, useful for region-specific copy.

Browser coverage includes Chrome, Firefox and Edge, with integrations across common writing services.

Premium tiers include both browser and Word workflows, while Premium Plus removes the monthly optimization ceiling.

Duden states that text is encrypted, excluded from AI training and deleted after checking.

Cons

German-only checking excludes multilingual writing.

Internet access is mandatory, so offline editing is not supported.

Basis is capped at 500 characters without an account, and Pur at 10 monthly corrections or reformulations.

All paid plans use annual billing and annual cancellation, reducing short-term flexibility.

No mobile or desktop app is provided; Word support is limited to specified macOS and Windows versions.

Alternatives

For a broader reference library, compare Online Dictionaries; for dedicated correction tools, see Grammar checkers. ABBYY Lingvo is a freemium dictionary platform spanning Android, iOS, macOS and Windows, so it is a better fit when dictionary access across devices matters more than German style correction. MDBG Chinese Dictionary suits Chinese dictionary and learning needs, with free online tools and broad platform coverage. Oxford Learner’s Dictionaries is preferable for English learners who want free A–Z dictionary access, word lists and a text checker. Van Dale Online is a paid dictionary service with a school trial and school licensing. WordWeb offers a free Windows version with definitions, synonyms, examples, basic AI suggestions and translations. dict.cc provides free browser dictionary use for private and business purposes. Larousse Dictionaries combines free online reference content with a premium subscription. GoldenDict is a free GNU GPLv3+ dictionary application whose content is downloaded separately.

Verdict

Duden-Mentor is the right choice for German writers who want correction and style advice directly in browsers or supported Word versions, especially when regional German variants and privacy assurances matter. Choose Premium Plus for unbounded editing, or Premium when 250 monthly optimizations are enough. Look elsewhere for multilingual, mobile, desktop-native or offline writing support, and for plans without annual payment commitments.

Verdict

Duden-Mentor covers German correction and style suggestions across browser fields and supported Word versions. The free plan has stated limits, while paid tiers differ in monthly optimization allowances and included tools.

Where Specifiction places it

Alternatives to Duden-MentorAll alternatives →