Is there an AI assistant that works inside Outlook?

Yes: Microsoft 365 Copilot is built into Outlook, where it drafts emails, summarizes long threads and coaches your tone, and it is the best choice if your company already has Copilot licenses because nothing extra touches your mail. If you do not have that license, an add-in such as MailMaestro or Grammarly works inside Outlook too, and the free lesson Choose the AI Assistant Your Team Should Use shows why the tool your company already pays for usually wins.

The confusing part is licensing. Microsoft offers a free Copilot Chat to many business accounts, but Microsoft's own answers say it mostly helps with the email or thread you have open. The full Copilot in Outlook, which can draw on your inbox, calendar and files, comes with a Microsoft 365 Copilot license for work accounts. Ask IT which one you have before you buy anything.

What are the options, and what decides between them?

• Microsoft 365 Copilot. Draft with Copilot writes a full email from a short prompt and the thread, and the Summarize button sits at the top of a thread. With the full license it uses your mail, files and meetings for context and respects your company's existing permissions. Deciding factor: your company has the license, or will buy it.
• MailMaestro. An add-in you install from Microsoft's add-in store. It summarizes threads and attachments and offers several drafts in the tone, length and language you choose. Its site lists Outlook on the web, classic Outlook and Outlook for Mac. Deciding factor: no Copilot license, and you want help inside the Outlook you already use.
• Grammarly. Checks grammar, tone and clarity as you type, and rewrites or drafts text with AI. It works in Outlook as well as Gmail, Word and the browser. Deciding factor: you mostly want better wording, not full drafts.
• Superhuman. A separate email app that connects to Outlook accounts, with Auto Drafts that learn from your past emails and reminders when nobody replies. Deciding factor: you are willing to leave the Outlook app for speed.
• Canary Mail. A separate secure email app that connects to Outlook and Exchange accounts, with AI that drafts and summarizes on its paid plans. Deciding factor: you want encryption and a different app on Mac, Windows or phone.

For the bigger picture, see the best AI email assistants, Copilot vs Gemini for work email and Copilot Chat vs Microsoft 365 Copilot.

How do I find out what I can use?

1. Look for the Copilot icon in Outlook's ribbon or above a message. If it is there, try Summarize on a long thread.
2. Ask IT whether you have Copilot Chat or a full Microsoft 365 Copilot license, and whether add-ins are allowed.
3. Check the add-in policy. Many companies block third-party add-ins that read mail.
4. Test on one real thread: a summary, then a reply. Check every date and promise.

What does this look like in a real lesson?

In the four assistants lesson you are the office manager at an insurance agency. You paste the same task, a client reminder email plus a table of the week's tasks, into ChatGPT, Claude, Gemini and Microsoft Copilot. In Copilot your name shows a Work badge, meaning it can use company files and email if the company allows. You ask Copilot for an even shorter version, then score each answer on the date, the request for the VIN and the phone number. All four pass, and you pick Copilot Chat because the agency already pays for Microsoft 365.

For the reply itself, Reply Faster: Customer Emails shows the routine any assistant needs: give it the thread and the facts you can promise, ask it to check every promise against those facts, then fix the one line that overpromises before you send.

What mistakes should I avoid?

• Assuming the free Copilot Chat sees your whole inbox. It usually works on the open message.
• Installing an add-in IT has not approved. It reads your mail, so it needs the same review as any vendor.
• Pasting client email into a personal AI account to get around a missing license.
• Sending drafts unread. Check names, dates and anything that sounds like a promise.

Key takeaways

• Microsoft 365 Copilot is the built-in Outlook assistant; check which license you have.
• MailMaestro and Grammarly work inside Outlook without Copilot.
• Superhuman and Canary Mail are separate apps that connect Outlook accounts.
• Use what your company allows, and read every draft.

Frequently asked questions

Is Copilot in Outlook free?

Many business accounts get Copilot Chat at no extra cost, but the full Outlook features need a Microsoft 365 Copilot license. Some personal Microsoft 365 plans include Copilot too.

Can ChatGPT work inside Outlook?

ChatGPT runs in its own app or browser tab. You can paste a thread into it, or connect your work accounts if your plan and admin allow it. Inside Outlook itself, the built-in assistant is Copilot.

Which Outlook assistant writes in my own style?

Superhuman and Fyxer learn from your sent emails. See which email assistant writes replies that sound like you.