--- title: "Grammar Checker: Fix Spelling and Grammar with AI" description: "Free AI grammar checker: fixes spelling, grammar and punctuation in English, Portuguese, Spanish and more, and marks every change it made." url: "https://www.utillab.net/grammar-checker" language: "en" --- # AI Grammar Checker Fix spelling, grammar and punctuation in any text, and see exactly which words were removed and which were added. TXT, PDF, DOCX, EPUB or subtitles. Read in your browser. Your text and the answer are kept with your account and processed by AI providers through OpenRouter, which may keep them. Do not include personal or sensitive data. 0 / 8,000 characters Guide ## Checking a text and reviewing every change ### What it checks The checker proofreads your text the way a careful editor would on a first pass: spelling and accents, agreement between subject and verb, verb forms, punctuation, and words that are clearly wrong in context. It is told to change only what is wrong, so your vocabulary, your tone and your paragraphs stay as you wrote them. Unlike a spell checker that only knows a list of words, a language model reads the sentence as a whole, so it can catch a correctly spelled word in the wrong place, such as their for there, or a verb that no longer agrees after you edited the subject. ### How to use the grammar checker 1. Paste or type your text: an e-mail, an essay, a post, a cover letter or a résumé. You can also import a TXT, PDF, DOCX or EPUB file, read in your browser. 1. Sign in with a free account if you have not yet; it gives 20 AI texts per day. 1. Click **Check grammar** and wait a few seconds. 1. Read the **What changed** block: removed words are struck through in red, new words are in green. 1. Copy the corrected text, or keep your original where you disagree with a change. ### An example Text: "Me and him goes to the office every days, but yesterday we was late." Correction: "He and I go to the office every day, but yesterday we were late." Four changes: the subject pronouns, the verb agreement, "every day" and "were". The sentence keeps its meaning and its casual tone; only the errors are gone. ### Reading the changes - A word struck through and a new one right after it is a replacement: a misspelling, a wrong verb form or a wrong word. - A green comma, accent or word alone is something missing that was added. - A red word alone is something that should not be there, such as a repeated word. - The count in the title tells you at a glance whether the text needed a touch or a lot of work. ### Limits AI corrections are very good but not infallible. The model may not know a proper name, a brand, a technical term or a deliberate informal spelling, and correct it anyway; it can also miss an error in a long, complex sentence. Keep what you meant and ignore a change that alters it. For long documents, check one section at a time, up to 8,000 characters, so every part gets a careful read. The checker fixes errors; it does not judge style. If you want shorter sentences, plainer words or a more formal voice, use the paraphrasing tool or the tone changer after the check. ### Before you send For an important e-mail, an application or a text that will be published, read the corrected version once, aloud if you can. It is the best way to catch what no tool sees: a sentence that is correct but says something you did not mean. ## Frequently asked questions about the grammar checker ### What does the grammar checker fix? Spelling, accents, grammar such as agreement and verb forms, punctuation and clear word errors. It keeps your language, your tone, your meaning and your paragraph breaks, and changes only what is wrong, so the corrected text still reads like yours. ### How do I see the corrections? Under the corrected text, the What changed block shows the removed words struck through in red and the new words in green, with the number of changes. You can review every correction before you copy the text, and ignore one you do not agree with. ### Does it rewrite my style? No. It is told to fix only clear errors and to leave style alone: it does not make sentences shorter, swap words for fancier ones or change the tone. For a different style or tone, use the paraphrasing tool or the tone changer instead. ### Which languages can it check? Any language the model knows well: English, Portuguese, Spanish, French, German, Italian, Russian, Japanese, Hindi and many others. It checks the text in its own language and does not translate it; it respects regional spelling, such as Brazilian or European Portuguese, as written. ### Is it free? How long can the text be? Yes, with a free account: 20 AI texts per day, shared with the other AI writing tools of the site, up to 8,000 characters each, about four pages. For a longer document, import it and check one part at a time. ### What does it mean when no mistakes are found? The model returned your text unchanged, so it found nothing to fix. A correct text checked again gives the same answer at once in the same tab, without using your daily limit. It can still miss a mistake, especially in names and technical terms. ### Can it miss mistakes or change something correct? Yes, occasionally. It may not know a proper name, a brand, a technical term or a deliberate informal spelling, and treat it as an error. Read the marked changes and keep what you meant; you have the final word on your text. ### Is my text stored? Yes. The text you send and the answer are kept with your account to prevent misuse, and are deleted when you delete the account. To produce the answer, the text goes through OpenRouter to AI model providers, which may keep it under their own rules, so do not include personal or sensitive data. Requests that break the Terms of Use are refused automatically. Last updated: November 14, 2026