AI Grammar Checker — Fix Errors Without Changing Your Voice

Fix grammar, spelling, and punctuation without changing your voice. See exactly what changed and why.

AI Grammar Checker fixes objective errors — grammar, spelling, punctuation, capitalization — without rewriting your voice. The biggest complaint about Grammarly and similar tools is that they suggest style changes you didn't ask for, slowly homogenizing your writing. Pickrack's checker is the opposite: it fixes only what's wrong, leaves voice and style alone.

Powered by Claude Haiku 4.5 with a strict system prompt: only flag spelling errors, missing articles, subject-verb mismatches, punctuation mistakes. Style preferences (Oxford comma, sentence length, word choice) are NOT changed unless they're objectively wrong.

Output: corrected text + a list of every issue with the original phrase, the fix, and a brief reason. Verify the changes before accepting — AI can occasionally over-correct in domain-specific writing.

Key features

Voice-preserving — Won't suggest style changes. Won't replace your word choice with a "simpler" alternative. Only fixes objective errors.
Issue-by-issue diff — Every change shown with original → fix + reason ("subject-verb agreement", "missing article", "misspelling"). Decide which to accept.
Multilingual — Works for English, Vietnamese, Spanish, French, German, and other major languages. For Vietnamese, catches diacritic errors, sai chính tả, and pronoun confusion.
Free, no signup — 10 checks per IP per day. Sustainable for casual writing without paying for Grammarly Premium ($12/mo) or ProWritingAid ($10/mo).
Privacy-first — Your draft is sent to Anthropic for processing, then the response is returned. Anthropic does not use API inputs for training. Pickrack stores nothing.

How to use

Step 1: Paste your text — Up to 6,000 characters per check. For longer pieces, run paragraph-by-paragraph.
Step 2: Click Check — Haiku analyzes in 2-5 seconds and returns corrections + reasons.
Step 3: Review and accept changes — Each issue is shown separately. Click to accept or skip individual fixes. Copy the final corrected text.

When to use

Final proofread of a blog post before publishing — catch typos and grammar without losing your voice
Polish an email to a client — fix subject-verb errors that an autocorrect missed
Check a Vietnamese essay for chính tả and grammar without it suggesting Westernized phrasing
Verify a college application essay — focus on objective errors, not style preferences
Quick review of a Slack message before sending — small grammar fix, no style preaching
Check translated text that came from another tool (DeepL, Google Translate) for grammar quality

Frequently asked questions

How does this compare to Grammarly?

Grammarly does grammar + style + tone + clarity + plagiarism on a paid tier. Pickrack does grammar + spelling + punctuation only, free with a daily quota. The narrower focus means fewer noisy suggestions — Grammarly users often disable style/tone hints because they over-correct. If you want full editing assistance, use Grammarly. If you want errors fixed without rewriting, use Pickrack.

Will it change my word choice?

Only if the word is objectively wrong. "Affect" vs "effect" will be fixed if used wrongly. "Buy" will not be changed to "purchase" — that's a style preference, not an error.

Does it work in Vietnamese?

Yes. Catches dấu (diacritic) errors, common chính tả mistakes ("dấu" vs "giấu", "chính" vs "chánh"), and basic grammar issues. Less aggressive on style — Vietnamese style varies by region and audience.

Will it preserve markdown / formatting?

Yes — bullets, paragraphs, bold, italic, code blocks are kept intact. Code blocks are NOT checked (they're not prose).

How many words can I check at once?

6,000 characters per check, which is roughly 1,200 English words. For longer pieces (essays, articles), run paragraph-by-paragraph or split by section — Claude is consistent across runs, so the suggestions stay coherent.

Does it catch comma splices, semicolon errors, em-dashes?

Yes for objective errors (e.g., comma where a period is grammatically required). For style preferences (Oxford comma, em-dash vs en-dash usage), it leaves them alone.

What about plagiarism or AI-detection?

Out of scope — this tool is grammar only. For plagiarism, try Copyscape or Quetext. For AI-detection (which is unreliable in 2026 anyway), see GPTZero or Originality.ai.

Is there a usage limit for the grammar checker?

10 checks per IP per 24 hours. Reset is rolling, not midnight-based — slots free up exactly 24 hours after each use. For heavier use, install a desktop alternative (LanguageTool open-source server is the closest free equivalent with no quota).

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