LanguageTool review 2026: see how this open-source, multilingual grammar and style checker compares on features, pricing tiers and Grammarly alternatives.
Category
Productivity
Pricing
Freemium, from Free (Premium from about $4.17/month billed every 2 years)
LanguageTool is a grammar, spelling and style checker that started as an open-source research project in 2003 and has since grown into a commercial product used by writers, students, businesses and developers who need multilingual proofreading beyond what English-only tools provide.
The platform blends thousands of hand-written grammar rules with machine-learning and generative-AI models, giving it both a reliable rule-based foundation and modern AI-powered rewriting and paraphrasing capabilities, all while keeping an open-source core engine publicly available.
Key Features
LanguageTool checks grammar, spelling, punctuation and style across more than 30 languages and regional variants, and ships as browser add-ons, desktop apps, mobile keyboards, document-editor integrations, and a developer API.
Premium unlocks over 20,000 additional style and grammar checks, a much higher character limit per document, unlimited AI paraphrasing, and a custom style guide for enforcing consistent terminology across a team or organization.
Pricing
LanguageTool offers a genuinely usable free Basic plan alongside an Individual Premium subscription billed monthly, quarterly, annually or every two years, with per-month cost dropping sharply the longer the commitment.
A Teams plan adds centralized billing, a shared style guide and dictionary for organizations with 2 to 20-plus members, while larger companies can opt for Business/Enterprise deployment including self-hosting options.
Key Features
Multilingual grammar checking — Checks grammar, spelling and punctuation across 30-plus languages and regional variants, most maintained by volunteer native-speaker linguists.
AI-powered paraphrasing — Premium unlocks unlimited AI sentence rewriting to improve clarity, tone and style; the free plan allows a few paraphrases per day.
Browser and desktop integration — Available as add-ons for Chrome, Firefox, Edge and Safari, plus native desktop apps for Windows, macOS and Linux.
Custom style guide — Premium and Teams users can define preferred terminology and phrasing rules enforced consistently across documents.
Developer API and self-hosting — A REST API and self-hostable server package let businesses embed checking into their own products or run the engine on-premise for data privacy.
Team dictionary and management — Teams plans add a shared dictionary for technical terms, email-based member management, and centralized billing.
Document editor integrations — Works natively inside Google Docs, Microsoft Word, Outlook, and OpenOffice/LibreOffice.
Open-source core engine — The underlying rule-based engine is open source on GitHub, letting the community contribute rules and new language support.
Pros & Cons
Pros
Genuinely usable free tier compared to most grammar-checker competitors
Strongest multilingual support in the category, covering 30-plus languages
Open-source core allows self-hosting for data-sensitive organizations
Two-year plan pricing is significantly cheaper than Grammarly's comparable tiers
Works across a wide range of browsers, desktop apps and document editors
Cons
AI writing/rewriting features are less extensive than Grammarly's full suite
Interface and suggestions can feel less polished than newer AI-first competitors
Monthly billing is comparatively expensive versus the discounted annual/2-year plans
Some advanced style checks are limited to fewer languages than English
Team pricing is not transparently listed and may require inquiry for larger seats
Pricing
Basic (Free) Free N/A
Premium Monthly $24.90/month Monthly
Premium Annual $7/month (billed annually) Annual
Premium 2-Year $4.17/month (billed every 2 years) Biennial
Teams Custom per-seat pricing Varies
Frequently Asked Questions
Is LanguageTool free to use?
Yes, LanguageTool offers a free Basic plan with core grammar and spelling checks, a 2,000-character limit per text, and three free paraphrases per day.
How many languages does LanguageTool support?
LanguageTool supports more than 30 languages and regional variants, including English, German, French, Spanish, Portuguese, Dutch, Italian, Polish, Russian, Ukrainian, Chinese and Japanese.
Is LanguageTool open source?
Yes, the core rule-based checking engine is open source and available on GitHub, and it can be self-hosted by organizations that need on-premise deployment.
How does LanguageTool compare to Grammarly?
LanguageTool offers broader multilingual support and a self-hosting option, while Grammarly has a larger AI-writing feature set and is more English-focused with wider brand recognition.
What is included in LanguageTool Premium?
Premium adds over 20,000 additional grammar and style checks, a 150,000-character limit per text, unlimited AI paraphrasing, a custom style guide, and access to all supported languages.
Does LanguageTool offer a Teams plan?
Yes, Teams plans support 2 to 20-plus members with all Premium features plus a shared Team Style Guide, Team Dictionary, and centralized billing.