Word's spell-check catches most typos, but not the ones that look like real words

Microsoft Word underlines misspelled words with a red squiggle as you type. Right-click the squiggle and Word suggests corrections. This works well for obvious mistakes — "teh" becomes "the", "recieve" becomes "receive". But Word cannot tell the difference between words that are spelled correctly but used wrong, like "their" versus "there" or "to" versus "too". It also misses technical terms, proper names, and industry jargon unless you add them to your custom dictionary.

The spell-check feature is turned on by default in Word. If you do not see red squiggles under misspelled words, check the Review tab at the top of the window and look for "Spelling & Grammar" — click it to run a full check of your document at once rather than waiting for Word to flag things as you type.

Key Takeaways

  • Word's red squiggle catches spelling errors but not wrong word choices like "their" instead of "there".
  • Right-click a red squiggle to see Word's suggestions, or use the Review tab to check your whole document at once.
  • Word ignores words in your custom dictionary, so add technical terms and proper names you use often to stop false flags.
  • Grammar checking is separate from spelling and catches some sentence problems, but misses many — read your work aloud to catch what Word misses.
  • Spell-check works only on the language you tell Word you are using, so set your document language correctly if you write in multiple languages.

How to add words to your custom dictionary so Word stops flagging them

When Word underlines a word you know is correct — a company name, a technical term, a surname — right-click it and select "Add to Dictionary". Word will stop flagging that word in any document you write from that point forward. The custom dictionary lives on your computer, not in the cloud, so it only works on the device where you added the word.

If you work on the same documents across multiple computers or use Word online, you will need to add words to the dictionary on each device separately. There is no way to sync a custom dictionary across devices in Word's free or standard versions. If your team uses the same technical terms repeatedly, the faster solution is often to ignore the squiggles rather than add dozens of words one at a time.

The difference between spelling and grammar checking

Spelling checks whether a word is spelled correctly. Grammar checks whether you used the right word in the right place and whether your sentence structure is sound. Word has both tools, but they work separately. You can turn grammar checking on or off without affecting spelling, and vice versa.

To turn grammar checking on, go to File, then Options, then Proofing, then check the box next to "Check grammar with spelling". Word will then underline grammar problems with a blue squiggle. These suggestions are less reliable than spelling suggestions — Word often flags correct sentences as wrong and misses real errors. Use grammar checking as a second set of eyes, not as a final authority. Reading your work aloud catches far more problems than any automated tool.

Why Word misses errors that look like real words

Word's dictionary contains hundreds of thousands of words, but it cannot understand meaning. If you type "I went to the store to buy some flower" when you meant "flour", Word sees nothing wrong — "flower" is spelled correctly. The same happens with homonyms: "there", "their", and "they're" are all spelled correctly, so Word does not flag them even when you use the wrong one.

Word also cannot catch errors that depend on context. "The board of directors are meeting" is grammatically debatable depending on whether you treat "board" as singular or plural, and Word may or may not flag it depending on your grammar settings. Sentences that are technically correct but awkward or unclear slip past entirely. This is why spell-check is useful for catching typos but not for catching mistakes in word choice or logic.

How to run a full spell-check on your entire document

Click the Review tab at the top of the Word window. In the Proofing group, click "Spelling & Grammar". Word will open a panel on the right side of your screen and move through your document one error at a time. For each flagged word or phrase, Word shows you suggestions. Click a suggestion to accept it, or click "Ignore" to skip it. Click "Ignore All" to skip every instance of that word in the document.

When Word finishes, it tells you how many errors it found and corrected. This full check is useful before you send a document to someone else, but it still misses errors that involve word choice or meaning. After Word finishes, read through your document yourself, especially sections you edited or rewrote — those are where mistakes hide.

Setting your document language so spell-check works correctly

Word spell-checks against the language you tell it you are using. If your document is set to Spanish but you wrote it in English, Word will flag almost every word as wrong. To check what language Word thinks you are using, go to the Review tab, click "Language", and look at what is selected. If it is wrong, select the correct language from the list.

If you write in multiple languages in the same document, select the text in each language and set its language separately. Highlight the English section, set it to English. Highlight the Spanish section, set it to Spanish. Word will then check each section against the right dictionary. This matters most if you write in two languages regularly — otherwise, set the whole document to your main language and ignore the squiggles in any borrowed words or names.

When to ignore Word's spell-check suggestions

Word sometimes suggests changes that are wrong. Proper names, brand names, and technical terms often get flagged even when they are spelled correctly. If you are writing about a person named "Saoirse" or a company called "Accenture", Word may suggest you change them — do not. Trust your source document over Word's suggestion when you know the spelling is correct.

Word also sometimes suggests changing a correct word to an incorrect one. If this happens repeatedly with the same word, add it to your dictionary so Word stops bothering you. If Word's suggestion seems odd, search the word online to confirm the correct spelling before you accept the change. A few seconds of checking beats sending a document with a mistake you introduced by trusting an automated tool.

Frequently Asked Questions

Why does Word not catch "their" when I meant "there"?

Both words are spelled correctly, so Word's spell-check does not flag them. Word's grammar checker can sometimes catch this error if you turn it on, but it misses many instances. The only reliable way to catch these errors is to read your work aloud or have someone else read it.

Can I turn off the red squiggles if they distract me while I write?

Yes. Go to File, then Options, then Proofing, and uncheck "Check spelling as you type". The squiggles will disappear. You can still run a full spell-check later using the Review tab. Many writers turn off live spell-checking while drafting and check spelling only when they are done writing.

Does Word's spell-check work the same way in Word online as it does in the desktop version?

Word online has spell-checking, but it is simpler than the desktop version. It catches spelling errors and some grammar problems, but has fewer options for customization. If you need advanced spell-checking features, use the desktop version of Word.

What happens to my custom dictionary if I uninstall Word?

Your custom dictionary is stored on your computer separately from Word itself. If you uninstall and reinstall Word, your custom dictionary usually stays. If you get a new computer, you will need to rebuild your custom dictionary on the new device.

Can I share my custom dictionary with my team?

Not easily in standard Word. Your custom dictionary is personal to your computer. If your team needs the same words added, each person has to add them individually, or you can ask your IT department about shared dictionary options if your organization uses Word through a business subscription.