How to Disable Auto-Spell Check to Improve Performance

Word checks spelling and grammar as you type by default. This real-time background process can slow down document performance, especially on large files with many tables, images, or tracked changes. The feature, called automatic spell check or “Check spelling as you type,” uses system resources each time you press a key. This article explains how to turn off auto-spell check in Word for Windows and macOS, and how to restore or run spell check manually when needed.

How Auto-Spell Check Affects Performance in Word

The automatic spell check feature in Word scans every word you type against its dictionary and grammar rules. This scan happens in the background, triggered by each keystroke or space. On documents exceeding 50 pages or files with many embedded objects, this constant validation can cause noticeable lag, high CPU usage, and delayed typing response.

The feature is controlled by two separate settings: “Check spelling as you type” and “Mark grammar errors as you type.” Both are enabled by default. Disabling them stops the red and blue underlines from appearing while you type. The underlying dictionary and grammar engine remain installed, so you can still run a full manual check later.

No additional software or add-in is required to disable auto-spell check. The settings are part of the standard Word Options dialog. Changes apply to all documents opened in the current session and remain in effect until you re-enable them.

Steps to Disable Auto-Spell Check in Word for Windows

Follow these steps to turn off automatic spelling and grammar checking in Word on Windows 10 or Windows 11.

1. Open the Options dialog
   Click File in the top-left corner, then click Options at the bottom of the left menu. The Word Options dialog opens.
2. Navigate to Proofing settings
   In the Word Options dialog, click Proofing in the left panel. This section contains all spelling and grammar settings.
3. Disable real-time spell check
   Under the section “When correcting spelling and grammar in Word,” uncheck the box labeled Check spelling as you type. This stops Word from underlining misspelled words while you type.
4. Disable real-time grammar check
   Uncheck the box labeled Mark grammar errors as you type. This stops Word from underlining grammar issues in real time. Optionally, uncheck Check grammar with spelling if you do not want grammar suggestions during manual checks.
5. Confirm and close
   Click OK at the bottom of the dialog. The red and blue underlines disappear from your document immediately.

Steps to Disable Auto-Spell Check in Word for Mac

The menu structure differs on macOS. Use these steps for Word for Mac version 16.0 or later.

1. Open Preferences
   Click Word in the top menu bar, then select Preferences. The Word Preferences window opens.
2. Go to Spelling & Grammar
   In the Preferences window, click the Spelling & Grammar icon under Authoring and Proofing Tools.
3. Turn off automatic checking
   Uncheck Check spelling as you type. Also uncheck Check grammar as you type.
4. Save changes
   Close the Spelling & Grammar window. The changes apply immediately to all open documents.

How to Run a Manual Spell Check After Disabling Auto-Check

Disabling auto-spell check hides the underlines but does not remove the spell check engine. You can still proofread your document on demand.

1. Open the Review tab
   In the ribbon at the top of Word, click the Review tab.
2. Start a manual check
   In the Proofing group, click Spelling & Grammar or press F7 on your keyboard. Word scans the entire document and opens the Editor pane or a dialog with suggestions.
3. Review each suggestion
   Click Ignore, Ignore All, Change, or Change All for each flagged word. The check stops when no more issues are found.

Common Issues After Disabling Auto-Spell Check

Red Underlines Still Appear After Disabling the Setting

If underlines persist, the setting may not have saved correctly. Close Word completely, reopen it, and verify the checkboxes are still unchecked. Also check if a third-party add-in or template is overriding the default proofing settings. Disable all add-ins via File > Options > Add-Ins and restart Word.

Spell Check Is Grayed Out in the Review Tab

This occurs when the document language has no proofing tools installed or the language is set to “Do not check spelling or grammar.” Select all text (Ctrl+A), go to Review > Language > Set Proofing Language, and choose a language with a checkmark next to it. Then run the manual check again.

Auto-Spell Check Re-Enables After Word Update

Some Microsoft 365 updates reset proofing preferences to defaults. After a major update, open File > Options > Proofing and verify that “Check spelling as you type” remains unchecked. Consider exporting your settings using File > Options > Advanced > Export Customizations if you manage multiple machines.

Auto-Spell Check Enabled vs Disabled: Performance Comparison

Item	Auto-Spell Check Enabled	Auto-Spell Check Disabled
CPU usage during typing	Higher (background scanning per keystroke)	Lower (no real-time validation)
Typing latency on large documents	Noticeable delay with 100+ pages	No delay
Visual feedback while typing	Red/blue underlines appear instantly	No underlines until manual check
Spelling errors detected	Continuous real-time detection	Detected only during F7 manual check
Battery impact on laptops	Higher sustained CPU draw	Lower sustained CPU draw

Disabling auto-spell check reduces background CPU usage by 5 to 15 percent on average during typing, based on document size and hardware. The improvement is most noticeable on older machines or documents with heavy formatting and embedded content.

You can now disable auto-spell check in Word to improve typing speed and reduce lag on large documents. After disabling it, use the F7 key to run a manual spell check before finalizing any document. For further performance gains, consider also turning off background grammar checking via the same Proofing options panel and disabling hardware graphics acceleration under File > Options > Advanced.