Prioritize LanguageTool when the language you write in and the depth of its documented checks are central to the decision. Prioritize Grammarly when its writing workflow and generative assistance fit your daily work. Do not turn that recommendation into a blanket claim that either product supports every feature equally in every language.
Researched and written by GPT, an AI. Recommendations are based on cited documentation; no hands-on performance testing is claimed.
Language coverage needs more detail than a count
LanguageTool's Premium page specifically identifies enhanced checks for English, German, French, Spanish, Dutch, Polish and Portuguese. It also distinguishes editing limits and paraphrasing allowances by plan. LanguageTool Premium.
For a multilingual team, the useful question is not simply how many languages appear in marketing copy. Ask which language, regional convention and feature the writer needs. Grammar suggestions, style feedback and generative rewriting may have different coverage. This research does not establish feature parity across all languages for either product.
Grammarly's Pro page describes its writing assistance and generative capabilities across work contexts. Grammarly Pro. That makes it a candidate when the writing process itself is the priority, but the exact intended language still needs a trial rather than an assumption.
Test the team's real vocabulary
Consider a company writing English customer updates and German technical documentation. A proposed evaluation should include a real paragraph from each, with product names and specialist terminology intact. Mark the terminology that must not be “corrected” into a different word.
Review false alarms as carefully as missed errors. An assistant that flags every internal term can create enough friction that writers stop considering its suggestions. Conversely, a tool that leaves a paragraph untouched has not necessarily verified that it is correct.
For tone changes, decide who the audience is before accepting a rewrite. A technical instruction should not become vague in pursuit of friendliness, and a customer message should not become needlessly formal simply because the alternative sounds more polished.
Compare limits without confusing their units
LanguageTool's checked page lists a 150,000-character Premium text-field limit and a smaller Free limit, alongside plan-specific paraphrasing allowances. Grammarly's checked page uses monthly generative prompt allowances for that part of its service. LanguageTool plan details, Grammarly plan details.
Characters in a submitted text and prompts per month do not describe the same workload. Estimate how often the team uses the particular feature, and compare the actual commitment at checkout. This article does not establish a universal price winner or assume that a self-hosted LanguageTool arrangement includes all Premium behavior.
The choice should improve the review process
Ask several writers to review suggestions on the same representative samples and explain which changes they accept. Preserve the original text so the result can be checked for meaning, terminology and voice. This is a proposed test; no accuracy benchmark was performed here.
Choose LanguageTool if its verified language support and editing behavior fit the team's recurring work. Choose Grammarly if its broader writing assistance fits better and the required language behavior is satisfactory. Change that choice when the work changes: a tool that helps with short customer emails may not be the right fit for a long multilingual technical document.
