Every free grammar checker fixes the same narrow slice of a draft: a typo, a wrong verb form, a missing comma, a doubled word. That layer is useful, and free from half a dozen companies — which means the honest reason people paid for Grammarly was never the grammar. It was the rewriting: tone, clarity, plagiarism checks and the AI features around them are the paid part. If spelling and agreement are your problem, you can switch today and lose almost nothing.
There is also a branding reason not to over-commit. Grammarly’s parent company rebranded as Superhuman in October 2025 after buying Coda and the Superhuman mail client, and in March 2026 it pulled its AI “Expert Review” feature after a class-action lawsuit and a backlash from authors (Wired, March 2026). The checker itself is unchanged and still good. The free-versus-paid line moves every year, so pick a tool you can leave. As of late September 2026, these are the free layers worth keeping.
What the free layer really catches
A free checker reads for rules, not meaning: a misspelled word, a stray apostrophe, a verb that does not agree with its subject. It misses what a human editor catches — a sentence that is grammatical but lands wrong, a paragraph that repeats itself, a claim that needs a source. That gap is the paid jump, which is why every upsell page sells “clarity” and “tone” rather than commas.
LanguageTool
LanguageTool is the pick when you want the checker to behave like software rather than a service. Its core is open source, it checks well over twenty languages rather than English alone, and the same engine runs in the extension and the desktop app. Free covers spelling, grammar and punctuation; style suggestions, longer text and paraphrasing sit behind Premium (check languagetool.org for pricing). The reason to prefer it is control — the engine can be self-hosted, so text never leaves a machine you own.
Microsoft Editor
Microsoft Editor is the free tier people forget is free, because it never looks like one. Sign in with a Microsoft account and you get spelling, grammar and a basic clarity check inside Edge, Word and Outlook. The catch is familiar: rewrite, tone and deeper style suggestions come with a Microsoft 365 subscription. It is the weakest of this group on nuanced prose and the easiest to switch on: fine for email, poor as your only editor.
ProWritingAid
ProWritingAid is the one to try if your complaint is repetition rather than typos. Its differentiator is the report: it counts sticky sentences, overused words and pacing across a whole manuscript. The free tier is capped by word count per check; paid plans run about $30 per month billed monthly or roughly $10 per month billed yearly, with a lifetime licence around $399 (prowritingaid.com/pricing; check the official site) — a rare one-time option in this category.
Screenshot of the ChatGPT interface via Wikimedia Commons (public domain).
Hemingway Editor
Hemingway Editor is not a grammar checker, which is why it pairs well with one. The free web version grades readability and highlights adverbs and passive voice; it gives no comma advice and no synonyms. For a second pass on a post or a report, a grade level and a list of flagged sentences beat another set of comma rules. The desktop version is a small one-time purchase.
A free assistant pass
For the paragraph that survives every checker and still sounds wrong, paste the draft into ChatGPT or Claude and ask for a proofread that preserves your voice. Both free tiers handle a full document in one pass, which no inline checker does; the trade-off is a usage reset, not a word cap. Our ChatGPT tool page covers the free plan.
What the comparison tables leave out
Every extension here reads the pages you visit and sends what you type to a server. That is the product, not a defect, but the consequences matter. Grammarly’s own Chrome extension once leaked authentication tokens to any site that asked — a flaw Google researcher Tavis Ormandy found in 2018, catalogued as CVE-2018-6654, patched within hours. A tool that reads every form you fill is a high-value target. The quieter issue is retention: free accounts generally let the provider keep your text to train models unless you opt out, so a sentence typed into a client contract may sit on someone else’s server. If that bothers you, use a desktop app, self-host LanguageTool, or paste only text you would be happy sending.
How to combine them
Keep one checker always on for everyday writing — LanguageTool if you want control, Microsoft Editor if you live in Edge and Word — and treat it as the floor, not the finish line. When a long piece is nearly done, run it through ProWritingAid’s report and Hemingway’s readability grade, then ask a free assistant about the paragraphs neither flagged. For a resume the order is different: matching the job description matters more than style, which is why our guide to AI tools for resume writing starts with the posting. Our roundup of the best free AI writing tools covers the wider $0 stack.
Written from official product pages and public reporting checked in late September 2026. Free-tier limits and pricing change often — check each site before subscribing.