Spell check is on by default in Word, but you may need to turn it back on if you disabled it

Microsoft Word runs spell check automatically as you type. Red squiggly lines appear under words it does not recognize, and you can right-click any underlined word to see suggestions or add it to your dictionary. If spell check is not working, it is usually because you turned it off in settings, not because it failed to start.

The steps to turn spell check back on differ slightly between Windows and Mac versions of Word, and between the desktop app and Word online. All three routes take less than a minute.

Key Takeaways

  • Spell check runs automatically in Word as you type and shows red underlines under unrecognized words.
  • On Windows Word, go to File > Options > Proofing and check the box next to "Check spelling as you type".
  • On Mac Word, go to Word > Preferences > Spelling and Grammar and check "Check spelling as you type".
  • In Word online, go to Editor Settings and toggle on "Spelling" under the Proofing section.
  • If you see red underlines but spell check still seems off, you may have added words to your personal dictionary that you want to remove.

Turn on spell check in Word for Windows

Open Word and go to the File menu in the top left. Click Options near the bottom of the menu. A window will open with a list of categories on the left side.

Click Proofing in that list. You will see a section called "Spelling" with several checkboxes. Make sure the box next to "Check spelling as you type" is checked. If it is already checked, spell check is on. If it is unchecked, click it to turn spell check on. Click OK at the bottom right to save and close the window.

Spell check will start working immediately. Any misspelled words in your document will show red underlines. Words that are spelled correctly but not in Word's dictionary will show blue underlines (these are grammar or style suggestions, not spelling errors).

Turn on spell check in Word for Mac

Open Word on your Mac. Click Word in the menu bar at the very top of the screen, then click Preferences. A window will open with several icons.

Look for the icon labeled Spelling and Grammar and click it. A new window will appear. Check the box next to "Check spelling as you type". If it is already checked, spell check is already on. If you want to turn it on, click the box and then close the window.

Spell check will begin working right away. Red underlines will appear under words Word does not recognize. You can right-click any underlined word to see suggestions or add it to your dictionary so Word stops flagging it.

Turn on spell check in Word online

Open Word online in your web browser and sign in with your Microsoft account. Click the Editor button in the top right corner of the ribbon (it looks like a pen in a circle). A panel will open on the right side of the screen.

At the top of the Editor panel, click Editor Settings (the gear icon). Scroll down to the Proofing section. Make sure the toggle next to Spelling is turned on (it will be blue when on). Close the settings panel by clicking elsewhere in the document.

Spell check will now run as you type. Misspelled words will show red underlines. Click any underlined word to see suggestions from the Editor panel on the right.

What to do if spell check is on but not working

If spell check is turned on but you are not seeing red underlines, the problem is usually that you have added words to your personal dictionary. Word stops flagging any word in your dictionary, even if it is misspelled. To check this, right-click a word you know is misspelled. If the context menu does not appear or shows no spelling suggestions, the word is in your dictionary.

To remove a word from your dictionary on Windows, go to File > Options > Proofing and click Custom Dictionaries. Select the dictionary file and click Edit Word List. Find the word you want to remove and delete it. On Mac, go to Word > Preferences > Spelling and Grammar and click Dictionaries, then find and remove the word the same way.

Another reason spell check might seem off is if you have changed the language setting. If your document is set to a language you do not use, Word will flag many correct words. Check the language by going to Review > Language (Windows) or Review > Spelling and Grammar > Language (Mac), and make sure it matches the language you are writing in.

How to use spell check suggestions

When you see a red underline, right-click the word to open a menu of suggestions. Click any suggestion to replace the misspelled word with the correct spelling. If none of the suggestions are right, you can type the correct spelling yourself by clicking in the word and editing it directly.

If a word is spelled correctly but Word does not recognize it (like a proper name or technical term), you can click Add to Dictionary from the right-click menu. Word will stop flagging that word in any document you write. Be careful with this option — if you add a misspelled word by mistake, you will need to remove it from your dictionary later.

Frequently Asked Questions

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

Word's dictionary does not include every word in the English language, especially proper names, technical terms, and newer words. If a word is correct but underlined, right-click it and click Add to Dictionary. Word will stop flagging it in future documents.

Can I turn off spell check for just one document?

Yes. On Windows, go to File > Options > Proofing and uncheck "Check spelling as you type". This turns spell check off for all documents. To turn it off for one document only, go to Review > Language and set the language to "Do Not Check Spelling or Grammar".

What is the difference between red and blue underlines?

Red underlines mark spelling errors — words that are misspelled or not in Word's dictionary. Blue underlines mark grammar and style suggestions, like awkward phrasing or repeated words. You can turn off blue underlines separately in the Proofing settings if you only want spelling feedback.

Does spell check work in Word on my phone or tablet?

Yes, spell check works in Word for iPhone, iPad, and Android. It works the same way as the desktop version — red underlines appear as you type, and you can tap a word to see suggestions. The settings are usually on by default and can be adjusted in the app's settings menu.