Where Is Spell Check in Outlook 365 — And How to Control It

Spell check in Outlook 365 is one of those features that quietly works in the background — until it doesn't. Whether it's underlining everything in red, missing obvious errors, or simply not running at all, knowing exactly where to find and manage it puts you back in control of your emails.

How Spell Check Works in Outlook 365

Outlook 365 uses two overlapping layers of spell checking:

AutoCorrect fixes errors as you type — swapping common misspellings with the correct word in real time, often before you even notice the mistake.

Spell check on send scans your message right before it goes out, flagging anything that looks wrong with a pop-up prompt. This is the safety net that catches what AutoCorrect misses.

Both layers pull from the same dictionary settings, and both can be configured independently. Understanding which one you're working with matters — because disabling one doesn't affect the other.

Finding Spell Check Settings in Outlook 365 🔍

The Main Spelling & AutoCorrect Menu

The core settings live here:

1. Open Outlook 365
2. Click File in the top-left corner
3. Select Options from the left-hand menu
4. In the Outlook Options window, click Mail
5. Scroll to the Compose messages section
6. Click Spelling and Autocorrect...

This opens the Editor Options panel — the central control room for everything spell-check-related in Outlook.

Inside Editor Options

Once you're in Editor Options, you'll see several categories on the left. The relevant ones are:

• Proofing — controls when and how spell check runs, which dictionaries it uses, and what types of errors it flags
• AutoCorrect Options — manages real-time corrections, text replacements, and capitalization rules

Within Proofing, the most important settings include:

Running a Manual Spell Check

If you're drafting a message and want to run spell check on demand — without waiting for the send prompt:

1. Click anywhere inside the body of your email
2. Press F7 on your keyboard

Or navigate to the Review tab in the ribbon while composing a message and click Spelling & Grammar.

This triggers a full scan of your current draft, walking through flagged words one at a time with suggestions. ✅

Why Spell Check Might Not Be Working

Several things can quietly break spell check in Outlook 365:

Language settings mismatch. If the language assigned to your email text doesn't match the installed proofing language, Outlook won't flag errors. This happens frequently when pasting text from external sources — the pasted content can carry its own language tag. You can check this by selecting your email text, going to Review > Language > Set Proofing Language, and confirming the correct language is selected.

"Do not check spelling or grammar" is enabled. This option is sometimes set accidentally — especially after pasting formatted content. It's found in the same Set Proofing Language menu. If this box is checked for selected text, spell check will skip it entirely.

Shared settings with Word. Outlook 365 uses the same proofing engine as Microsoft Word. Changes made to spell check settings in Word can carry over to Outlook, and vice versa. If spell check behaves unexpectedly, it's worth checking Word's proofing settings too.

Add-ins or template conflicts. Certain Outlook add-ins or custom email templates can interfere with the proofing engine. Running Outlook in Safe Mode (hold Ctrl while launching it) temporarily disables add-ins, which helps isolate whether one is causing the problem.

Custom Dictionaries — Adding Words Outlook Doesn't Recognize

When Outlook flags a word that's actually correct — a name, a brand, a technical term — you have two options:

• Ignore Once / Ignore All — skips the word for this session or this document
• Add to Dictionary — permanently adds the word so it's never flagged again

To manage your custom dictionary directly (remove words you've accidentally added, for example):

1. Go to File > Options > Mail > Spelling and Autocorrect > Proofing
2. Click Custom Dictionaries
3. Select CUSTOM.DIC (the default) and click Edit Word List

Spell Check in New Outlook vs. Classic Outlook

Microsoft has been rolling out a redesigned New Outlook interface, and the settings path differs slightly from the classic view.

In New Outlook, spell check settings are accessed via: Settings (gear icon) > Mail > Compose and reply > Spelling

The options are somewhat simplified compared to classic Outlook — AutoCorrect customization in particular is more limited in the new interface. Users who rely heavily on custom AutoCorrect entries or complex proofing configurations may find classic Outlook's Editor Options more flexible.

Whether the simplified New Outlook settings are sufficient — or whether the fuller controls in classic Outlook matter — depends on how and where you draft your messages. 🖊️

The Variables That Shape Your Experience

Spell check behavior in Outlook 365 isn't uniform across every user. The version you're running (classic vs. new Outlook), your Microsoft 365 subscription tier, the languages you write in, and whether your organization uses managed IT policies can all affect which settings you see and what you can change.

IT-managed environments sometimes lock specific proofing settings at the admin level, meaning individual users can't override them. Home and personal subscribers typically have full access to every option described here. That's before factoring in how you personally compose email — inline, in templates, using dictation, or pasting from other tools — each of which interacts with spell check differently.