How spell check works in the programs you already use

Spell check is a built-in feature in nearly every word processor and email program. It compares the words you type against a dictionary, marks words it does not recognize with a red underline, and suggests corrections when you right-click them. In Microsoft Word, Google Docs, and most browsers, spell check runs automatically as you type — you do not have to turn it on or run it manually.

The feature catches obvious misspellings like "teh" or "recieve", but it has limits. It will not catch words spelled correctly but used wrong — "their" instead of "there", or "its" instead of "it's". It also flags proper nouns and technical terms it does not know, even when they are spelled right. Understanding what spell check can and cannot do helps you use it as a tool rather than relying on it completely.

Key Takeaways

  • Spell check is automatic in Word, Google Docs, Gmail, and most browsers — red underlines appear as you type, and right-clicking shows suggestions.
  • Spell check catches misspelled words but not words used in the wrong context, like "their" for "there" or "accept" for "except".
  • You can add words to your personal dictionary so spell check stops flagging them — useful for names, brand names, and technical terms you use often.
  • Grammar checkers like Grammarly catch some context mistakes spell check misses, but they work alongside spell check, not instead of it.

Spell check in Microsoft Word

Word underlines misspelled words with a red squiggle as you type. To see suggestions, right-click the underlined word. A menu appears with corrections ranked by likelihood — the top option is usually the one you want. Click it to replace the word when ready.

If you misspell a word repeatedly, Word learns the pattern. To stop Word from flagging a word you know is correct — a last name, a product name, or a technical term — right-click it and select "Add to Dictionary". That word will no longer be marked as wrong in any document you write. To manage your dictionary later, go to File > Options > Proofing > Custom Dictionaries, where you can view, edit, or delete words you have added.

Word also has a full spell check you can run manually. Go to Review > Spelling & Grammar. A panel opens on the right showing every flagged word in your document. You can ignore individual instances, ignore all instances of that word, change it, or add it to your dictionary. This is useful if you want to check an entire document at once rather than fixing words as you notice them.

Spell check in Google Docs

Google Docs marks misspelled words with a red underline. Click the underlined word and a small menu appears with suggestions. Click the suggestion you want, or click the three-dot menu to add the word to your dictionary or ignore it for that document only.

Google Docs does not have a separate "run spell check" button — it checks continuously as you type. If you want to see all flagged words at once, go to Tools > Spelling and Grammar. A panel opens listing every error in the document. You can navigate through them one by one, accept suggestions, or dismiss them. This view is helpful when you are finishing a document and want to catch anything you missed.

Words you add to your dictionary in Google Docs sync across all your Google accounts and devices. If you add "Salesforce" to your dictionary on your laptop, it will not be flagged when you type it on your phone or tablet.

Spell check in email and browsers

Gmail, Outlook, and most email programs include spell check. In Gmail, misspelled words are underlined in red. Right-click to see suggestions or add the word to your dictionary. Outlook works the same way — red underlines appear as you type, and right-clicking shows corrections.

Most web browsers — Chrome, Firefox, Safari, Edge — also check spelling in text boxes and email compose windows. The red underline appears the same way. Right-click to correct it. Browser spell check uses your system dictionary, so words you add in one program may or may not appear in another, depending on your operating system.

Adding and managing your personal dictionary

Your personal dictionary is where spell check stores words you have told it are correct. This is essential if you write about specialized topics, use brand names, or write in multiple languages.

In Word, add words through the right-click menu or manage them at File > Options > Proofing > Custom Dictionaries. You can create separate dictionaries for different topics — one for medical terms, one for your industry jargon — and turn them on or off depending on what you are writing.

In Google Docs, words are added automatically when you click "Add to dictionary" from the spell check menu. You cannot create separate dictionaries or view your full list, but you can remove a word by going to Tools > Spelling and Grammar, finding the word, and clicking "Remove".

In browsers and email, the dictionary is usually managed by your operating system. On Windows, go to Settings > Time & Language > Spelling. On Mac, go to System Preferences > Keyboard > Text. You can see words you have added and remove them if needed.

What spell check misses and what to do about it

Spell check will not catch homophones — words that sound the same but are spelled differently and mean different things. "Their", "there", and "they're" are all spelled correctly, so spell check ignores them even if you use the wrong one. The same is true for "accept" and "except", "affect" and "effect", or "its" and "it's".

Spell check also will not catch words that are spelled correctly but used in the wrong context. If you write "I am going to the store to by milk", spell check sees "by" as a correctly spelled word and does not flag it, even though you meant "buy".

For these mistakes, a grammar checker is more useful than spell check alone. Grammarly is the most common tool — it is available as a browser extension, a Word add-in, and a standalone app. It catches context mistakes, suggests clearer phrasing, and checks for tone. Grammarly's free version catches most common errors. The paid version offers more detailed feedback and style suggestions. Other options include Microsoft Editor (built into Word and available as a browser extension) and LanguageTool (free and open-source).

Turning spell check off and on

In most cases, you want spell check on. But if you are typing code, writing in a language spell check does not support, or testing something intentionally misspelled, you may want to turn it off temporarily.

In Word, go to File > Options > Proofing and uncheck "Check spelling as you type". To turn it back on, check the same box. In Google Docs, go to Tools > Spelling and Grammar and toggle it off. In Gmail, you cannot turn off spell check entirely, but you can ignore individual words by right-clicking and selecting "Ignore".

In browsers, right-click the text box and uncheck "Check spelling" if the option appears. This disables spell check for that text box only, not for your entire browser.

Frequently Asked Questions

Why does spell check flag words I know are correct?

Spell check uses a standard dictionary that does not include all proper nouns, brand names, or technical terms. If you use a word often, add it to your personal dictionary so it stops being flagged. This is especially useful for names, product names, and industry-specific terminology.

Can I use spell check in multiple languages?

Yes. In Word, go to Review > Language and select the language you are writing in. Google Docs automatically detects the language, but you can change it at Tools > Language. Most browsers let you add multiple languages to your spell check dictionary in settings.

Does spell check work on my phone or tablet?

Yes, but it depends on the app. Gmail, Outlook, and Google Docs all include spell check on mobile devices. The feature works the same way — tap a flagged word to see suggestions. Your personal dictionary syncs across devices if you use the same account.

What is the difference between spell check and grammar check?

Spell check finds misspelled words. Grammar check finds incorrect word usage, punctuation errors, and unclear phrasing. Spell check catches "teh" but misses "their" when you meant "there". Grammar check catches both. They work together, not as replacements for each other.

Can I add slang or informal words to my dictionary?

Yes. Your personal dictionary stores whatever you add to it. If you write casually and want spell check to recognize slang you use regularly, add it. Keep in mind that words in your dictionary will not be flagged even in formal writing, so you may want to review them before submitting professional documents.