Overview

The checker covers spelling, grammar and punctuation, then adds style suggestions for filler words, repeated words and overly long sentences. That combination is useful for polishing everyday writing as well as catching errors. Support for Germany, Austria and Switzerland gives writers a way to account for regional German variants. It checks German only, so anyone writing across languages will need another tool.

Key features

Browser extensions for Chrome, Firefox and Microsoft Edge can work in text fields on services such as Gmail, Web.de, GMX.de, Trello, Facebook and WordPress. This suits people who write directly in web services and want corrections where they compose, rather than moving text into a separate editor.

The Word add-in supports Microsoft Word for macOS from version 2016 and Windows from version 2019. Writers using those versions can bring the checker into a familiar workflow; people on other versions should confirm compatibility before choosing a paid plan. Duden-Mentor requires an internet connection, so it is not an option for offline editing.

Duden says text is transmitted encrypted, is not used for AI training and is deleted after checking. For business use, its product page specifies TLS 1.2 and a 128-bit key for transfer to AWS servers contractually located in Frankfurt, Germany. Duden customer service can offer personal help when the FAQ does not resolve a question.

Pricing

The free Basis plan is free. It allows 500 characters without an account and stores up to 10 words in the personal dictionary. That is enough for occasional short checks, but the character cap makes it unsuitable for regular document editing.

Pur costs 2.99 EUR per month, billed 35,88 € pro Jahr, with annual payment and annual cancellation. It includes 10 test corrections or reformulations per month. That is a low-cost way to try the service regularly, but the small monthly quota is restrictive for frequent writers.

Premium costs 7.95 EUR per month, billed 95,40 € pro Jahr, with annual payment and annual cancellation. It adds 250 text optimizations per month, browser extensions, the Word add-in and an unlimited personal dictionary. This is the practical choice for steady use across browser and Word workflows, provided 250 monthly optimizations are enough.

Premium Plus costs 9.95 EUR per month, billed 119,40 € pro Jahr, with annual payment and annual cancellation. It includes unlimited text optimizations, the browser extension, Word add-in and unlimited personal dictionary. Frequent writers who would exceed Premium's quota have a clear reason to pay the difference; occasional users are better served by the cheaper tiers.

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

Platforms

Duden-Mentor is offered on the web, as browser extensions and for macOS and Windows. It has no desktop or mobile app, so the listed computer platforms do not mean a standalone application. Browser and Word integrations are the main ways to use it in everyday writing.

Who it's for

Choose Duden-Mentor if you write German regularly, want both corrections and style guidance, and work in supported browsers or Word. The regional variants are a useful fit for writing aimed at readers in Germany, Austria or Switzerland. Look elsewhere if you need multilingual checking, offline access, a mobile app or a generous free allowance for longer texts.

Pros and cons

Pros: Checks spelling, grammar and punctuation while also flagging filler, repeated words and long sentences, making it useful for both correctness and readability.
Pros: Regional German support and browser and Word integrations fit writers working across supported services and documents.
Pros: Premium Plus removes the monthly optimization cap, while Premium offers a lower-cost 250-optimization tier.
Cons: German-only checking excludes multilingual writing workflows.
Cons: The free plan's 500-character check and Pur's 10 monthly corrections are limited for regular editing.
Cons: Paid plans are billed annually, and an internet connection is required.

Alternatives

For a broader dictionary selection, browse Online Dictionaries; for tools focused on error checking, compare Grammar checkers.

MDBG Chinese Dictionary is the better fit for Chinese dictionary and learning tools, with a free online plan and platforms including web, mobile and desktop. ABBYY Lingvo is a freemium dictionary alternative with mobile and desktop platforms. Oxford Learner’s Dictionaries offers free online access to its learner dictionaries, a text checker and word lists, making it a better match for English learners. Van Dale Online is a paid dictionary service with a school-license option and a free trial. Wordnik offers web and API access, with paid plans structured around hourly call limits. dict.cc provides a free web dictionary for private and business use. WordWeb is a free dictionary option for Windows and mobile platforms, subject to its licensing terms. GoldenDict is a free, GPL-licensed dictionary program for desktop and Android, with dictionary content downloaded separately.

Verdict

Duden-Mentor is a good choice for German writers who want grammar and spelling checks plus practical style guidance in browser fields or supported Word versions. Its regional German coverage and integrations make it more useful than a basic proofreader for that focused audience. Choose another tool if you need multiple languages, offline use or more room in a free plan; for paid use, make sure the annual commitment and monthly optimization allowance match your workload.

	Duden-Mentor	Merriam-Webster Legal Dictionary
Free plan	Yes
Free trial	Yes
Paid from	€2.99/mo
Platforms	extension, macOS, Web, Windows	Android, iOS, Web
Free plan	Yes	Yes
Browser extension	Yes
Desktop app	No
Mobile app	No
Style suggestions	Yes
Mobile apps		ios_android

Duden-Mentor vs Merriam-Webster Legal Dictionary

Duden-Mentor

Merriam-Webster Legal Dictionary