How we tested
All five tools were tested in July 2026 on their current paid tiers (or the free tier, where that is the headline product); scores reflect the versions available in that window. Criteria are weighted toward catch rate and style depth for individual writers, with language coverage and value weighted heavily for teams and multilingual use.
Grammar & Spelling Catch Rate
We seeded a 5,000-word English document with 120 planted errors (subject-verb disagreements, homophone swaps, comma splices, misused apostrophes, wrong-word errors, and technical-jargon mis-spellings) and counted true positives, false negatives, and false positives per tool against a corrected reference.
Style & Clarity Depth
We ran the same 45,000-word novel manuscript and the same 2,000-word business report through each tool's deepest analysis mode and recorded how many distinct style dimensions each tool reports on (pacing, dialogue tags, sentence-length variance, overused words, passive voice, readability grade), then had two reviewers score the actionability of each report on a five-point rubric.
Integrations & Workflow
We installed each tool's browser extension, native Word add-in, Google Docs integration, and desktop app (where offered) and counted the writing surfaces where suggestions appeared inline versus surfaces that required copy-paste into a separate editor.
Language Coverage
We ran the same 500-word passage in English, German, French, Spanish, Portuguese, and Dutch through each tool and recorded which languages received full grammar and style checks versus which fell back to spelling only or refused the text.
Value at Paid Tier
We priced one seat of each tool's standard paid plan (annual billing) against the free tier's real ceiling (word cap, prompt cap, or feature gates) and recorded what a heavy user actually has to pay in year one and over a five-year horizon.
We ran every tool through the same manuscripts, emails, and multilingual passages, so the differences below come down to the products, not the briefs. The full battery and per-criterion marks are above; the notes here cover where the ranking turned.
Why Grammarly leads
Grammarly wins on the dimension that decides this category for most English writers: how often the checker is actually there when you need it.
At $12/month on annual billing, Pro bundles grammar checking, AI rewriting, plagiarism detection, AI text detection, fluency suggestions, style guides, brand tones, snippets, and team analytics
, and
on G2, Grammarly has 4.7/5 from 12,969 reviews (Winter 2026 Grid Report top ranked)
. The 2026 Pro plan absorbed what used to be sold as Grammarly Business:
the Pro plan includes all of the advanced writing features included in Premium, such as tone suggestions and full-sentence rewrites, plus team features that were previously available only in the Business plan
. That means small teams no longer pay a premium for style guides and brand tones.
The trade-offs are real but narrow.
Grammarly is still the benchmark for English correction depth, but its false-positive rate on technical and domain-specific prose has gotten worse with each “AI” upgrade
. The parent-company rebrand is confusing on top of that:
on October 29, 2025, the parent company renamed itself from Grammarly to Superhuman, the company rebranded, not the writing product, which is still called Grammarly
, and the new Business tier of the combined suite is a real step up in price.
If you just want better AI writing tools for your team, the standalone Pro plan at $12/month/seat is the right call - you’d be paying an extra $21/seat/month for email features you may not use
.
When to choose ProWritingAid instead
ProWritingAid is the tool we recommend for any writer whose editing session runs on a full manuscript rather than a live email.
Where those tools are real-time correction layers, ProWritingAid is a document analysis platform. You write, paste in your content, and get twenty-something distinct reports: grammar check, style report, overused words, repeated sentence starts, pacing analysis, dialogue tags, cliché detection, consistency check, and more. For fiction writers, this depth is genuinely valuable and unmatched by anything else in this price range.
Its pricing story is the sharpest in the category:
current ProWritingAid pricing for 2026: free tier, Premium at $30/mo or $120/year, Premium Pro at $36/mo or $144/year, and lifetime pricing at $399 or $699
, and
Premium at $120/year undercuts Grammarly Premium ($144/year) by $24/year
. The $399 lifetime license remains unmatched.
Grammarly has never offered a lifetime deal
.
The narrow trade-off is workflow shape.
What ProWritingAid does not do is compete with Grammarly on integration coverage - there is no native Google Docs support beyond a Chrome extension workaround, and the tool is clearly optimized for desktop writing applications over browser-based workflows
, and its free tier is a short trial, not a sustainable plan (
the free plan includes a 500-word limit, 2 report runs per day, 10 rephrases per day, and 3 Sparks per day
).
For any writer whose day crosses languages, or any organization that cannot let sensitive text sit on a vendor’s servers, LanguageTool is the answer and it isn’t close.
Unlike competitors that treat non-English languages as an afterthought with superficial coverage, LanguageTool provides genuinely thorough checking for each supported language with thousands of language-specific rules developed and maintained by professional linguists and an active open-source community.
The privacy story is the other reason to buy:
the core engine is completely open source under LGPL, and organizations can self-host it on their own servers to ensure sensitive text never leaves their infrastructure, a critical requirement for legal firms, government agencies, and healthcare organizations
.
The price is also the lowest in our test.
The annual Premium plan at $4.99/month ($59.90/year) is significantly cheaper than Grammarly ($12/mo) and ProWritingAid, making it the most affordable premium grammar tool for individual users in 2026
. Two real limits remain:
No. LanguageTool does not include a plagiarism checker on any plan, free or premium. If plagiarism detection is important for your work, use Grammarly Premium, Turnitin, or iThenticate as your primary plagiarism tool.
Premium features also don’t extend to self-hosted deployments, a long-standing gap the vendor has yet to close.
What did not make the cut
QuillBot is a credible generalist for one specific reader (a student who needs paraphrasing, plagiarism, and grammar in one subscription), and
as of June 13, 2026, QuillBot lists Premium at $19.95/month, $39.95 billed quarterly (about $13.31/month), or $99.95 billed annually (about $8.33/month)
. But its grammar engine trails Grammarly and ProWritingAid on the same 120-error battery, and the free tier’s paraphraser cap is aggressive:
QuillBot’s free tier provides access to the core paraphrasing tool with a 125-word input limit per paraphrase and 2 modes (Standard and Fluency)
. It earns a recommendation only as a focused tool for students and ESL writers.
Hemingway Editor is the one tool in our test we mark Not Recommended as a primary grammar checker.
Hemingway Editor supports Grammar Check, but it does not include Spell Check or Punctuation Check. Instead, it offers Text Editing (42%), which gives users another way to refine clarity and readability as they revise content. This can help businesses improve written communication quality while giving teams a simpler way to review and polish documents before publishing or sharing.
The desktop app is genuinely affordable:
The desktop version, Hemingway App, is available for a one-time payment of $19.99. The price is the same for both Windows and Mac. Purchasing Hemingway software also entitles you to free upgrades whenever they are available.
The readability visualizer remains excellent, but as a primary editing tool it’s too narrow on grammar and languages to carry the workflow.
Questions Readers Ask
Which AI grammar checker do you recommend?
We recommend Grammarly for English-focused professional writers on the strength of its catch rate, integration footprint, and 4.7/5 average across more than 12,000 G2 reviews. For long-form writers and novelists, we recommend ProWritingAid; its 20-plus writing reports and its $399 lifetime license make it the deepest and cheapest long-term option. For multilingual writers or teams that need to self-host, LanguageTool is the answer.
Is the free plan really enough, or will I need to pay?
That depends on the tool and how you write. LanguageTool's free tier is the most generous, requires no sign-up, and covers basic grammar and spelling in 30-plus languages. Grammarly's free plan handles spelling, grammar, and basic tone plus 100 AI prompts per month, which is enough for casual proofreading. QuillBot's free paraphraser is capped at 125 words per run. ProWritingAid's free plan is limited to 500 words per check. Hemingway Editor's free web version is unlimited but only handles readability, not real grammar checking.
Which tool is best for writers working in more than one language?
LanguageTool. It supports 30-plus languages with per-language rule sets developed and maintained by professional linguists and an active open-source community, and its Premium engine runs more than 20,000 additional style and grammar checks for English, German, French, Spanish, Dutch, Polish, and Portuguese. Grammarly and ProWritingAid are English-only in 2026.
Which grammar checker is safest for regulated industries?
LanguageTool is the only major tool that offers self-hosting under an open-source LGPL license, so sensitive text never leaves your infrastructure, the deployment pattern legal, healthcare, and government teams typically require. Grammarly holds a SOC 2 (Type 2) report and layers on SAML SSO, SCIM, BYOK encryption, and data-loss prevention at the Enterprise tier, which is quote-based.
Why did Hemingway Editor fall short of a recommendation?
Hemingway is still the best readability visualizer in the category, but the category has moved past it on the dimensions our rubric weights most heavily. Its proofreading tool is thin (reviewers consistently note it misses grammar errors a full checker would catch), it does not integrate natively into Google Docs, Word, or the browser, and it supports English only. We mark it Not Recommended as a primary grammar-and-writing checker; it remains an excellent supplementary readability tool alongside Grammarly or ProWritingAid.
