You want to change the tone of an email draft in the new Outlook for Windows or Outlook on the web using Copilot. The Draft with Copilot feature includes a Tone button that lets you switch between Casual, Formal, and other options. This article explains what each tone does, how to apply it, and what happens when you use it on existing drafts versus new messages.
Microsoft added the Tone adjustment to give you control over how your message sounds without rewriting everything manually. You will learn the exact steps to change the tone, the differences between Casual and Formal, and common pitfalls to avoid. This guide covers the current behavior in the new Outlook as of early 2025.
Key Takeaways: Using Draft with Copilot Tone in New Outlook
- Draft with Copilot > Tone button: Changes the formality level of your email text between Casual, Formal, and other presets.
- Casual tone: Uses contractions, shorter sentences, and friendly language. Suitable for coworkers you know well.
- Formal tone: Uses complete sentences, no slang, and polite phrasing. Suitable for executives, clients, or external contacts.
What Draft with Copilot Tone Does and How It Works
The Draft with Copilot feature in the new Outlook generates email text based on a prompt you enter. After Copilot creates the draft, you can click the Tone button to change the writing style. The tone adjustment rewrites the selected text or the entire draft to match the chosen formality level.
Microsoft uses a large language model to analyze the existing text and then regenerates it with different word choices, sentence structures, and punctuation. Casual tone adds contractions like “don’t” and “we’ll” and uses shorter paragraphs. Formal tone removes contractions, uses full titles, and adds polite phrases such as “I would appreciate” or “Thank you for your consideration.”
The tone feature is available in the new Outlook for Windows (version 1.2024.x or later) and Outlook on the web. You need a Microsoft 365 Copilot license to access Draft with Copilot. Free or Basic Outlook accounts do not have this feature.
Steps to Adjust the Tone in Draft with Copilot
These steps apply to the new Outlook for Windows and Outlook on the web. The interface looks similar on both platforms.
- Open a new email message
Click New Mail in the top-left corner of the Outlook window. A blank message window opens. - Launch Draft with Copilot
Click the Copilot icon in the ribbon or select Draft with Copilot from the Message tab. A text box appears where you type your prompt. - Enter your prompt
Type a description of what you want the email to say. For example: “Let the team know the project deadline moved to next Friday.” Click Generate. Copilot creates a draft and inserts it into the email body. - Click the Tone button
Look for the Tone button in the Copilot toolbar that appears above or below the generated text. The button shows a sparkle icon with the word “Tone.” Click it. - Select Casual or Formal
A dropdown menu opens with tone options: Casual, Formal, Professional, Neutral, and sometimes Fun or Creative. Click Casual to make the text friendlier. Click Formal to make it more professional. - Wait for the rewrite
Copilot regenerates the draft with the new tone. The process takes 2 to 5 seconds. The old text is replaced entirely. - Review and edit
Read the rewritten draft. Make manual edits if the tone does not fit perfectly. You can click Tone again to switch to a different option.
Applying Tone to an Existing Draft You Wrote Manually
You can also use the tone adjustment on text you typed yourself. Select the paragraphs you want to change. Then click the Copilot icon and choose Rewrite with Copilot. In the Rewrite panel, click Tone and pick Casual or Formal. Copilot rewrites only the selected text.
Common Mistakes and Limitations When Using Tone
Copilot Changes the Meaning of the Email
Sometimes the tone adjustment alters the specific details or intent of the message. For example, a Formal rewrite might remove a deadline date or change a request into a command. Always proofread the output before sending. Keep the original draft in a separate notepad file so you can restore it if the rewrite goes wrong.
Tone Button Is Grayed Out or Missing
The Tone button appears only after Copilot generates a draft. If you close the Copilot toolbar, you cannot access the tone adjustment without regenerating the draft. To bring the toolbar back, click Draft with Copilot again and type a new prompt. You can also use Rewrite with Copilot on existing text to see the Tone button.
Casual Tone Sounds Too Informal for Some Recipients
The Casual tone can include slang, emojis, or overly friendly phrases like “Hey there!” If you are writing to a client you have never met, the Casual tone may appear unprofessional. Use the Professional tone as a middle ground between Casual and Formal.
Formal Tone Adds Unnecessary Wordiness
The Formal tone sometimes makes simple requests sound overly complicated. For example, “Please send the report” might become “I would be grateful if you could provide the report at your earliest convenience.” If the message is too long, edit the draft manually to shorten it.
Casual vs Formal Tone: Key Differences
| Item | Casual Tone | Formal Tone |
|---|---|---|
| Contractions | Uses contractions like “don’t” and “we’ll” | Avoids contractions; uses “do not” and “we will” |
| Sentence length | Short sentences, often under 15 words | Longer sentences with multiple clauses |
| Salutation | “Hi [Name]” or “Hey [Name]” | “Dear [Title] [Last Name]” or “Good morning [Name]” |
| Closing | “Cheers,” “Thanks,” or “Best” | “Sincerely,” “Best regards,” or “Yours faithfully” |
| Punctuation | Exclamation points and informal punctuation | Standard punctuation, no exclamation points |
| Slang | May include slang or casual expressions | No slang; uses standard vocabulary |
| Emojis | May include emojis | No emojis |
| Best use case | Internal team updates, informal reminders | External clients, executives, official correspondence |
The table above summarizes the main differences between Casual and Formal tones in Draft with Copilot. The actual output depends on your specific prompt and the context of the email. Test both tones on a sample message before using them in important communications.
You can now control the formality of your Copilot-generated emails in the new Outlook using the Tone button. Try switching between Casual and Formal on the same draft to see how the language changes. For quick access, remember that the Tone button appears only after you generate a draft with Copilot. If you need a middle ground, select the Professional tone instead of Casual or Formal.