What is the difference between a spell checker and a grammar checker?

A spell checker evaluates each word in isolation against a dictionary. A grammar checker analyses whole sentences for structural issues like wrong verb tense or misplaced modifiers. This tool focuses on spelling and common grammar patterns for fast, private proofreading.

Free Spell Checker

Paste or type your text and see misspelled words highlighted instantly with correction suggestions. Multi-language, private, all in your browser.

Spell Check Results — click any highlighted word for correction options

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What This Spell Checker Does

Type or paste text into the editor and every word is checked in real time against a full Hunspell dictionary for your chosen language. Misspelled words are highlighted in red in the results panel below the textarea; common grammar issues such as uncapitalised pronouns and incorrect article use are highlighted in amber. Click any highlighted word to see a correction menu with up to six suggestions — select one to apply it instantly across your entire text.

The errors panel below the editor lists every unique issue found alongside clickable correction chips. The stats bar tracks your word count, character count, sentence count and error count simultaneously. All processing runs entirely in JavaScript inside your browser — your text is never uploaded to any server, which makes it safe to proofread confidential documents, private messages and unpublished drafts without any privacy concern.

Tips for Getting the Best Results

Select the correct language before pasting. English (US) and English (UK) use different spellings — "colour" is correct in UK but flagged as an error in US mode, and vice versa for "color".
Right-click or click any red word to see suggestions. The first suggestion is almost always the most statistically likely correction — click it to apply across your whole text instantly.
If a word is flagged but you know it is correct (brand names, domain-specific terms, proper nouns), use the Ignore option in the correction menu to dismiss it for the current session without affecting other checks.
Amber grammar highlights catch common issues like lowercase "i" as a pronoun, incorrect article use ("a umbrella" instead of "an umbrella"), and uncapitalised brand names. Fix red errors first, then review amber ones.
After correcting spelling, use our Word Counter to verify your word count and reading time, and our Character Counter to check whether your text fits within platform-specific length limits for SEO meta descriptions, social media or SMS.
For long documents, check section by section. It is easier to review a focused 300-word passage than scroll through a 3,000-word highlighted document trying to locate every red word.

Frequently Asked Questions

How does this online spell checker work?

When you type or paste text, every word is extracted and checked against a Hunspell dictionary — the same open-source dictionary engine used by LibreOffice, Firefox and many other major applications. The dictionary is downloaded once into your browser cache when the page loads, then all subsequent checking happens locally with no network requests. Misspellings are identified by testing whether a word (or its capitalisation variants) exists in the dictionary's word list, then generating correction suggestions using an edit-distance algorithm that finds the most statistically likely intended word.

In addition to Hunspell's dictionary lookup, the tool runs a set of grammar pattern rules that catch issues no spell checker can identify: incorrect pronoun capitalisation, wrong article use ("a" versus "an"), and uncapitalised brand and product names. These rules operate on the full text using regular expressions, so they understand the word's context rather than checking it in isolation. The result is a two-layer check — dictionary spelling plus contextual grammar — that catches more meaningful errors than either approach alone.

Which languages are supported and how do I switch?

The Language dropdown in the toolbar lets you switch between English (US), English (UK), French, German, Spanish, Italian, Portuguese and Dutch. Each language uses a separate Hunspell dictionary file fetched from a public CDN. When you switch languages, the new dictionary is downloaded and the current text is re-checked automatically against the new word list. The loading banner reappears briefly while the dictionary loads; checking resumes the moment loading completes.

English (US) is the most comprehensive dictionary in this tool, with the largest word list and the most extensive grammar rule coverage. English (UK) is the recommended choice for British, Australian and New Zealand English — it recognises spellings like "colour", "organise", "licence" and "travelling" that US mode would flag as errors. For non-English languages, the Hunspell dictionary covers standard spelling but the grammar rules (pronoun capitalisation, article correction, brand name detection) are English-specific and will not fire. If the dictionary for a non-English language fails to load, the tool automatically falls back to English (US) with a notification.

Why are some correct words flagged as misspelled?

No dictionary is exhaustive. Technical jargon, proper nouns, brand names, newly coined terms, domain-specific vocabulary, chemical names, Latin phrases and deliberately stylised spellings may all be highlighted even when they are entirely correct. This is an inherent constraint of dictionary-based spell checking — the dictionary can only know about words that were included in it when it was compiled, and language evolves constantly. Niche professional vocabulary in medical, legal, engineering and technology fields is particularly prone to false positives.

The most practical way to handle false positives is to use the Ignore option in the correction menu. Clicking "Ignore" on a word removes it from the current session's error list without modifying your text, so subsequent checks in the same session treat it as correctly spelled. If you are working with a document that uses many specialised terms, consider running a broad first pass to fix genuine misspellings and then a second pass focused on any remaining flagged words. For SEO purposes, after correcting errors use the Word Frequency Counter to check that your keyword distribution is balanced — over-correcting to simpler words can inadvertently reduce keyword density.

What is the difference between spell check and grammar check?

A spell checker evaluates each word in complete isolation by asking one question: does this string of characters exist in the dictionary? It has no knowledge of what a word means, how it is being used, or what the words around it say. This means it cannot catch errors that produce valid words in the wrong context — "their" versus "there", "its" versus "it's", "affect" versus "effect", or "complement" versus "compliment" all pass spell check because every one of those words is correctly spelled, just used in the wrong place.

A grammar checker analyses sentences structurally, understanding parts of speech, verb tense, subject-verb agreement, clause structure and syntactic context. This allows it to catch errors that spell checking misses entirely. This tool occupies a middle position: it performs full Hunspell spell checking plus a targeted set of grammar pattern rules covering the most common contextual mistakes — pronoun capitalisation, article agreement and brand name casing. For documents where grammar matters as much as spelling (formal letters, academic submissions, client-facing copy), complement this tool's output with a dedicated grammar checker before finalising.

How does the correction system work — what happens when I click a suggestion?

Clicking a red highlighted word opens a context menu listing up to six suggested corrections ranked by statistical likelihood, calculated using an edit-distance algorithm. The algorithm generates all possible single-character edits to the misspelled word (deletions, transpositions, substitutions and insertions), then filters for words that exist in the dictionary and ranks them by how many independent edit paths lead to each candidate. The word reachable by the most different edit combinations is typically the most likely intended word and appears first in the list.

When you click a suggestion, it replaces every instance of that misspelled word in your text simultaneously using a case-preserving replacement — if "teh" appears at the start of a sentence (capitalised as "Teh"), the correction is applied as "The" rather than "the". This means you can fix every instance of a repeated misspelling with a single click rather than hunting through the document manually. For grammar issues (amber highlights), the correction menu shows the specific grammar rule that was triggered alongside the suggested fix, and clicking applies only the first occurrence rather than replacing globally, since grammar corrections depend on sentence context.

How many words can I check at once?

There is no enforced limit. All checking runs in your browser using JavaScript, so practical limits depend only on your device's memory and processing speed. On a modern desktop or laptop, documents of 10,000 words or more are checked in under a second. On older mobile devices, very large documents may cause a brief delay, but the tool will still complete the check — it will not time out or error. The textarea itself supports unlimited text entry.

For very long documents such as full-length articles, business reports or manuscript chapters, a practical approach is to check in sections of 1,000–2,000 words at a time. This makes it easier to review flagged words in their immediate context rather than scrolling through a long highlighted output. Paste a section, fix any errors, copy the corrected text out, then paste the next section. After correcting all sections, reassemble the document and do a final check of the full text to catch any errors that might occur at paragraph join points or that you missed during the sectional pass.

Is my text private — does anything get sent to a server?

Nothing you type or paste is ever sent to any server. The Hunspell dictionary files are downloaded once when the page loads (or when you switch languages) and cached by your browser, but after that everything runs entirely locally in JavaScript. The spell-checking algorithm, grammar rules, suggestion generation and correction application all execute inside your browser with zero network activity. You can verify this by opening your browser's developer tools network tab while typing — no requests are made after the initial dictionary load.

This privacy-first architecture is deliberate and applies across the entire Convixy tool suite. It means you can safely check confidential business documents, personal correspondence, unpublished manuscripts, legal drafts, medical records and any other sensitive content without any risk of data exposure. It also means the tool works fully offline once the page has loaded — you can disconnect from the internet and continue checking without any loss of functionality. The only exception is switching to a new language, which requires a network fetch to download the new dictionary file.

How is this different from the browser's built-in spell check underline?

Every modern browser underlines misspelled words in form fields using the operating system's built-in dictionary, but this native spell check has significant limitations. It provides no summary count of how many errors were found, no list of which words were wrong, no consolidated view of all unique errors, and no statistics about your text. Each word must be right-clicked individually to see suggestions, and there is no way to apply a correction across all instances of the same misspelling simultaneously.

This tool supplements the browser's native underline with a full structured error summary. The highlighted output panel shows your entire text with all errors marked at once, giving you a bird's-eye view of how many corrections are needed and where they cluster. The errors table below lists every unique error with all available suggestions as clickable chips. The stats bar shows error count and unique error count alongside word and character counts. And the one-click "apply to all" correction saves significant time on documents where the same word is misspelled repeatedly — a common problem when a writer consistently types a particular word incorrectly throughout a long document.

Can I use this for social media posts, email subject lines and headlines?

Yes, and it is particularly worthwhile for short-form content where a single typo is highly visible and costly to correct after publication. A misspelled word in a tweet, ad headline, email subject line or push notification is seen immediately by your entire audience before you can fix it, and in some platforms (like scheduled social posts or sent emails) it cannot be corrected at all after the fact. Running short copy through this tool takes seconds and eliminates that risk entirely.

For social media specifically, combine this tool with our Character Counter, which shows live progress bars for Twitter (280 characters), Instagram captions (2,200), LinkedIn posts (3,000) and TikTok bio (80). Get the spelling right here, then paste into the Character Counter to verify it fits within your target platform's display limit before scheduling. For ad copy and blog post titles, run the title through our Text to Slug Generator after spell checking to create a clean, matching URL slug — a misspelling in a slug can be embarrassing and is harder to fix after a page is indexed.

Does the spell checker work offline?

Yes. Once the page has fully loaded and the dictionary has been downloaded, all spell checking continues to work without any internet connection. The dictionary is cached by your browser after the first load, so on subsequent visits even the initial dictionary download may be served from cache rather than the network. All JavaScript logic — the Typo.js Hunspell engine, grammar rules, suggestion algorithm, correction application and statistics calculation — runs locally with no network dependency.

This makes the tool useful in low-connectivity situations: on flights, in areas with poor signal, in secure network environments that restrict outbound connections, or on devices with limited data plans. The one scenario that requires an internet connection is switching to a language you have not used before in your browser, which requires downloading the dictionary file for that language. Once a language's dictionary has been cached by your browser, it too will be available offline. Switching between previously used languages while offline will use the cached versions automatically.

Can I download my corrected text after checking?

Yes. Use the "Download .txt" button in the actions bar to save your current textarea content as a plain text file named checked-text.txt. This is useful when you have made multiple corrections directly in the editor and want to preserve the corrected version without manually copying it into another application. The download is triggered entirely in your browser using the Blob API — no server upload occurs and the file is created locally.

The "Copy Text" button copies the current textarea content to your clipboard instantly, ready to paste into any application — your CMS, word processor, email client, social media scheduler or code editor. For a complete writing workflow, check spelling here, copy the corrected text, paste it into our Word Counter to verify the final word count and reading time, then check character length in our Character Counter before publishing. If the text is a page title or blog post heading, converting it to a URL slug with our Text to Slug Generator as the final step ensures the slug matches the corrected version of the title exactly.