How to Add a Custom Word to PowerPoint Spell Check Dictionary

PowerPoint flags misspelled words with a red underline during presentations and editing. When you frequently use industry terms, product names, or acronyms that are not in the default dictionary, the red underlines become distracting. PowerPoint lets you add these custom words to your personal dictionary so they are no longer marked as errors. This article explains how to add a word to the PowerPoint spell check dictionary on Windows 11 and Windows 10, how to manage the custom dictionary file, and what to do if the word still appears as misspelled after you add it.

How PowerPoint Spell Check Handles Custom Words

PowerPoint uses two dictionaries during a spell check. The main dictionary is provided by Microsoft and cannot be edited. The custom dictionary, named default.dic on most systems, is a plain-text file that stores words you add. When PowerPoint checks spelling, it compares each word against both dictionaries. If the word is found in either, the red underline is removed.

The custom dictionary is shared across all Office applications on the same computer. Words you add from PowerPoint are also recognized in Word, Outlook, and Excel. The dictionary file is located in the user profile folder under %AppData%\Microsoft\Spelling. Each word is stored on a separate line in lowercase, though the spell check ignores case when matching.

Before adding a word, confirm the spelling is correct. PowerPoint does not check the spelling of words you add. If you add a misspelled word, it will never be flagged again unless you manually remove it.

Steps to Add a Custom Word to the PowerPoint Spell Check Dictionary

There are two main ways to add words. The first method works while you are editing a slide. The second method is better when you want to add multiple words at once or if the right-click method is not available.

Method 1: Add a Word During Slide Editing

1. Locate the flagged word
   Open your presentation and find the word with a red wavy underline. This indicates PowerPoint does not recognize it.
2. Right-click the word
   Right-click the underlined word to open the context menu. The menu shows spelling suggestions at the top.
3. Select Add to Dictionary
   Click Add to Dictionary in the context menu. The red underline disappears immediately. The word is now saved to the default custom dictionary.

This method adds one word at a time. If you have many custom words, use the next method instead.

Method 2: Add Multiple Words Through PowerPoint Options

1. Open PowerPoint Options
   Click File in the ribbon, then click Options at the bottom of the left pane. The PowerPoint Options dialog opens.
2. Go to the Proofing category
   In the left pane of the dialog, click Proofing. The right pane shows spelling and grammar settings.
3. Open Custom Dictionaries
   Click the button Custom Dictionaries. The Custom Dictionaries dialog appears.
4. Select the default dictionary
   In the dialog, the list shows one or more dictionary files. Select default.dic and click Edit Word List. A smaller dialog opens showing all words currently in the dictionary.
5. Add your words
   Type each word in the Word(s) field and click Add. Repeat for every word you want to include. When you finish, click OK to close the word list dialog.
6. Close all dialogs
   Click OK in the Custom Dictionaries dialog, then click OK in the PowerPoint Options dialog. Your custom words are now active.

The words you add through this method are saved to the same default.dic file. They will be recognized in all Office applications.

What to Do If the Word Still Shows a Red Underline

PowerPoint still flags the word even after adding it to the dictionary

This usually happens when the word is stored in a different custom dictionary than the one PowerPoint is currently using. In the Custom Dictionaries dialog, verify that default.dic is checked. If you see multiple dictionaries listed, make sure the correct one is enabled. You can also remove all other dictionaries by selecting them and clicking Remove.

Another cause is a corrupted custom dictionary file. Close PowerPoint, navigate to %AppData%\Microsoft\Spelling, and rename default.dic to default.old. Restart PowerPoint and add the word again using Method 1 or 2. PowerPoint creates a fresh dictionary file automatically.

The Add to Dictionary option is grayed out or missing

This occurs when the presentation is in a read-only mode or when the file is stored in a location where PowerPoint cannot write to the dictionary. Save a copy of the presentation to your local drive and try again. If the issue persists, check that your user profile has write permissions to the %AppData%\Microsoft\Spelling folder.

Custom words are not shared with other Office apps

By default, all Office applications on the same Windows user account share the same default.dic file. If Word does not recognize a word you added in PowerPoint, open Word, go to File > Options > Proofing > Custom Dictionaries, and confirm that the same dictionary file is selected. If Word uses a different dictionary, add the words again in Word or change the dictionary path to point to the same file.

PowerPoint Spell Check: In-App vs Custom Dictionary Methods

Item	Right-Click Add to Dictionary	Options > Custom Dictionaries
Number of words added at once	One	Multiple
Requires a flagged word	Yes	No
Can view existing custom words	No	Yes
Can remove words	No	Yes
Works in all Office apps	Yes	Yes

You now know two reliable ways to add custom words to the PowerPoint spell check dictionary. Use the right-click method for quick additions during editing. Use the Options dialog when you need to add or remove many words at once. If you ever need to reset the dictionary, delete the default.dic file from the %AppData%\Microsoft\Spelling folder and restart PowerPoint. For advanced users, you can also edit the default.dic file directly in Notepad by adding one word per line and saving the file as UTF-8 without BOM.