Spell Check is built into Word and runs automatically as you type

Microsoft Word checks your spelling in the background while you work. Red squiggly lines appear under words Word does not recognize — misspellings, proper nouns it has not learned, or words not in its dictionary. You do not have to turn anything on or search for a tool. The checking happens by default.

If you do not see red lines under words you think are wrong, spell check may be turned off, or you may be looking at a word that Word recognizes as correct even if it is not the word you meant. This guide shows you where to find spell check controls and how to use them.

Key Takeaways

  • Red squiggly lines under words mean Word has flagged them as potential spelling errors; right-click to see suggestions or add the word to your dictionary.
  • Spell check runs automatically in Word, but you can also run it manually by pressing Ctrl+A to select all text, then going to the Review tab and clicking Spelling.
  • If you do not see red lines, spell check may be off; turn it back on in File > Options > Proofing > Check spelling as you type.
  • Word's spell check catches misspellings but not wrong words used correctly — "their" instead of "there" — so you still need to read your work.

Right-click a red squiggly line to see spelling suggestions

When Word underlines a word in red, that is the spell checker flagging it. Right-click directly on the underlined word. A menu appears with suggested corrections at the top. Click the correct spelling to replace the word when ready.

If the word is correct but Word does not recognize it — a name, a technical term, or a word from another language — you can click "Add to Dictionary" at the bottom of the menu. Word will stop flagging that word in future documents. You can also click "Ignore All" to skip that word for the rest of the current document only.

Run a full spell check from the Review tab

To check your entire document at once instead of fixing words as you go, use the Review tab. Click the Review tab at the top of the Word window. Look for the button labeled "Spelling" (in newer versions of Word it may say "Spelling & Grammar"). Click it.

Word opens a panel on the right side of your screen showing each flagged word one at a time. For each word, you can click a suggested correction, click "Ignore Once" to skip just that instance, or click "Add to Dictionary" to teach Word the word. Word moves to the next flagged word after you make a choice. When the check is complete, Word tells you the document is finished.

Turn spell check back on if it is off

If you do not see any red squiggly lines and you know there are spelling errors in your document, spell check may be disabled. Click File in the top left corner. Scroll down and click Options. In the Options window, click Proofing on the left side.

Look for a checkbox that says "Check spelling as you type." If it is unchecked, click it to turn spell check back on. You should see red lines appear under misspelled words within a few seconds. Click OK to close the Options window.

Understand what spell check can and cannot catch

Spell check catches words that are misspelled — "recieve" instead of "receive" — or words it does not recognize. It does not catch words that are spelled correctly but used in the wrong place. If you write "I went their" instead of "I went there," spell check will not flag it because "their" is a real word spelled correctly.

This is why reading your work yourself is still important. Spell check is a safety net, not a complete proofreader. For catching wrong words used correctly, Word also has a Grammar tool in the same Review tab, which flags some — but not all — of these mistakes.

Customize which words Word ignores

If you use technical terms, brand names, or words from other languages regularly, you can add them to Word's dictionary so they stop being flagged. Right-click any red-underlined word and select "Add to Dictionary." That word will no longer be flagged in any document you create.

If you change your mind later, you can remove words from the dictionary, but the process is more involved and requires accessing Word's dictionary file directly. For most people, adding words as you go is the simplest approach. Word keeps a separate dictionary for each language, so adding a word to your English dictionary will not affect spell check in other languages.

Frequently Asked Questions

Why does spell check underline words I know are spelled right?

Word's dictionary does not include every word in English — especially proper nouns, technical terms, and newer words. If a word is correct, right-click it and click "Add to Dictionary" so Word learns it. After that, it will not be flagged again.

Can I turn off spell check completely?

Yes. Go to File > Options > Proofing and uncheck "Check spelling as you type." The red lines will disappear. You can still run a manual spell check anytime by clicking Review > Spelling, even if automatic checking is off.

Does spell check work the same way in Word Online as in the desktop version?

Word Online has spell check, but it works slightly differently. Red lines appear as you type, but the Review tab and Spelling button are in a different location. In Word Online, look for the Editor button (looks like a pen) in the top toolbar to access spelling and grammar tools.

What is the difference between spell check and grammar check?

Spell check looks for misspelled words. Grammar check looks for sentence structure problems, punctuation errors, and some word-choice mistakes. Both run automatically in Word, and both can be controlled from File > Options > Proofing. You can turn one on and the other off if you prefer.