Spell check is on by default in Word, but you may need to turn it back on if it was disabled
Microsoft Word checks your spelling as you type — red squiggly lines appear under words it does not recognize. If you do not see those lines, spell check is off. You can turn it back on in a few clicks, and you can also change what Word flags and how it behaves when you are working.
The steps differ slightly between Word on Windows, Word on Mac, and Word online. All three versions let you control spell check from the same general location: the Review tab or menu.
Key Takeaways
- Spell check runs automatically in Word and shows red underlines under words it does not recognize — if you see no underlines, it is turned off.
- On Windows and Mac, open the Review tab, find Spelling & Grammar, and click the button to turn it on.
- In Word online, go to Review, then Editor, then toggle Spelling on.
- You can right-click any underlined word to see suggestions, add it to your dictionary, or ignore it.
- Word lets you ignore certain words or turn off spell check for a whole document if you need to.
Turning spell check on in Word for Windows
Open your document in Word. At the top of the screen, click the Review tab. Look for the button labeled Spelling & Grammar — it usually shows a checkmark with an "A" next to it.
Click that button. If spell check was off, it will turn on and you should see red squiggly lines appear under misspelled words within a few seconds. If the button appears pressed or highlighted, spell check is already on.
If you do not see the Spelling & Grammar button, your ribbon may be collapsed. Click the arrow or expand icon on the right side of the Review tab to show all options.
Turning spell check on in Word for Mac
Open your document. Click the Review tab at the top. Find Spelling & Grammar in the ribbon and click it.
A small menu may appear asking whether you want to check the whole document or just from the cursor forward. Choose Check Document to scan everything. Word will highlight errors with red underlines.
If you want spell check to run continuously as you type (rather than only when you click the button), go to Word menu > Preferences > Authoring and Language Tools > Spelling, and make sure Check spelling as you type is checked.
Turning spell check on in Word online
Open your document in Word online (office.com). Click the Review tab. Look for Editor and click it.
A panel will open on the right side of your screen. At the top, you should see a toggle for Spelling. Make sure it is turned on (the toggle should be blue or highlighted). Once it is on, Word will underline spelling errors in red as you type.
Word online also includes grammar checking in the same Editor panel. You can turn grammar on or off separately from spelling if you want only one or the other.
What to do when you see a red underline
Right-click any word with a red underline. A menu will appear with suggestions for the correct spelling. Click the suggestion you want, and Word will replace the word.
If the word is spelled correctly but Word does not recognize it — a name, a technical term, or a word from another language — you have two options. Click Add to Dictionary to teach Word that word, so it will not flag it again in any document. Or click Ignore All to skip that word for the rest of this document only.
If you want to ignore a word just once, click Ignore instead of Ignore All.
Turning spell check off for a whole document
If you are working with a document that contains many words Word does not recognize — code, medical terms, names from another language — you can turn off spell check for just that document without affecting your other files.
On Windows or Mac, go to Review > Spelling & Grammar and click the button again to toggle it off. In Word online, go to Review > Editor and turn off the Spelling toggle.
You can also go to File > Options > Proofing (Windows) or Word > Preferences > Authoring and Language Tools (Mac) and uncheck Check spelling as you type to disable it across all documents. This is useful if you work with a lot of technical writing, but most people leave it on.
Why spell check might not be working even when it is on
If you have turned spell check on but still see no red underlines, check your document language. Word checks spelling against the language you have set. If your document is marked as a different language than the one you are writing in, spell check will not catch errors.
Go to Review > Language (Windows) or Review > Set Proofing Language (Mac). Make sure the language matches what you are writing. If you are writing in English, select English (United States) or English (UK) depending on your spelling preference.
Another reason spell check might seem off: if your document has very few errors, you may straightforward not see any red lines. Try typing a word you know is misspelled — like "teh" instead of "the" — to test whether spell check is actually running.
Frequently Asked Questions
Can I add a word to my dictionary so Word stops flagging it?
Yes. Right-click the underlined word and select Add to Dictionary. That word will no longer be flagged in any of your Word documents. If you change your mind later, you can remove it by going to File > Options > Proofing > Custom Dictionaries (Windows) or Word > Preferences > Authoring and Language Tools > Dictionaries (Mac).
Does spell check catch grammar mistakes too?
Word has a separate grammar checker called Editor (in newer versions) or Grammar Check (in older versions). Spell check only catches misspelled words. To check grammar, go to Review > Editor and make sure the Grammar toggle is on. Grammar errors usually appear as blue underlines.
Why does Word flag words that are spelled correctly?
Word uses a built-in dictionary and may not recognize proper nouns, technical terms, or words from other languages. Right-click the word and choose Ignore All to skip it in this document, or Add to Dictionary to teach Word that word permanently.
Can I turn spell check off just for one paragraph?
Not directly. You can select a paragraph and set its language to a different one, which will disable spell check for just that section. Highlight the text, go to Review > Language, and choose a language you are not using. Word will skip spell-checking that text.
Is spell check the same in Word desktop and Word online?
They work the same way, but Word online's spell check is slightly less detailed. Both flag misspelled words with red underlines and let you add words to your dictionary. Word desktop has more options for customizing what gets checked.