Copilot in Outlook vs AI Reply Writer: Microsoft's AI or one reply tool everywhere?
Microsoft Copilot in Outlook ("Draft with Copilot") compared with AI Reply Writer: what each needs, where each works beyond Outlook, and which to choose.
Copilot in Outlook is Microsoft's AI built into Outlook: "Draft with Copilot" writes an email or reply from a prompt with a chosen tone and length, and it can summarise threads and coach your writing, on eligible Microsoft 365 and Copilot plans. AI Reply Writer works in Outlook on the web too, and in 23 sites in total, from Gmail and LinkedIn to WhatsApp Web and Teams. Use Copilot if your organisation already licenses it; use AI Reply Writer for one reply tool across all your apps.
At a glance
| Copilot in Outlook | AI Reply Writer | |
|---|---|---|
| What it is | Microsoft's AI built into Outlook and Microsoft 365 | An AI reply writer: a ✦ AI Reply button inside the reply box |
| Where it works | Outlook on Windows, Mac and the web | 23 sites, including Gmail, Outlook, LinkedIn, WhatsApp Web, Instagram, Facebook, Slack and Teams |
| Reads the conversation | Yes, within Outlook | Yes — the thread you have open, plus photos and PDFs in Gmail, Outlook and WhatsApp Web |
| Review replies | Not part of Outlook | Yes — Google Business Profile and Trustpilot, reading the star rating |
| Free plan | Requires an eligible Microsoft 365 or Copilot plan | 20 replies a month |
| Paid plans | Part of Microsoft's Copilot licences — see Microsoft's pages | Starter $7, Elite $14, Ultra $29 a month |
| Browsers and phone | Outlook apps and Outlook on the web | Chrome, Edge, Brave, Opera, Vivaldi and Firefox; a web app on phones |
| Sends anything for you? | No — you review and send | Never — it fills the box, you press Send |
What Copilot in Outlook is
Microsoft has built Copilot into Outlook. In a new email or a reply, "Draft with Copilot" writes from your prompt, with options for tone and length; Copilot can also summarise a long thread and give coaching on the tone and clarity of an email you wrote. It works in the Outlook apps and Outlook on the web.
Access depends on licensing: for work accounts it comes with a Microsoft 365 Copilot licence, and Microsoft sets which consumer plans include it. Check with your IT team or Microsoft's pages for your account.
What AI Reply Writer is
AI Reply Writer adds a ✦ AI Reply button to Outlook on the web — both the full reply window and the quick reply box — on personal (outlook.live.com) and work (outlook.office.com) accounts. It reads the thread and attachments such as PDFs and photos, and writes a reply you edit and send. The same button works on 23 sites in total.
- Beyond Outlook: Gmail, LinkedIn, WhatsApp Web, Instagram, Facebook, Slack, Microsoft Teams and more.
- No mailbox access: it reads only the thread open on screen, when you press the button.
- A free plan, so no licence is needed to try it.
The main differences
Licence vs install
Copilot comes through Microsoft licensing, often decided by an organisation. AI Reply Writer is something an individual can install and use on a free plan today.
One app vs many
Copilot is deeply integrated into Microsoft 365. If your replies also go out on Gmail, LinkedIn, WhatsApp Web or social media, AI Reply Writer covers those with the same tool.
Desktop app vs web
Copilot works inside Outlook's desktop apps as well as on the web. AI Reply Writer works in Outlook on the web in your browser, not in the desktop app.
Pricing
Copilot in Outlook is included with eligible Microsoft licences; see Microsoft's pages for current plans and prices.
AI Reply Writer has a free plan with 20 replies a month, no card needed. Paid plans are Starter ($7 a month), Elite ($14) and Ultra ($29); higher plans unlock more advanced AI models and larger allowances, and teams can buy the same plans per member. See pricing.
Which should you choose?
- Use Copilot in Outlook if your organisation licenses Microsoft 365 Copilot and you work mainly in Outlook's desktop app.
- Use AI Reply Writer if you use Outlook on the web, do not have a Copilot licence, or reply across many apps beyond Outlook.
About this comparison: it is based on each product's public information as of October 2026, and both products change often — check the other product's own website for its current features and prices before you decide. Product names are trademarks of their owners; AI Reply Writer is not affiliated with them.
Frequently asked questions
Do I need a licence to use Copilot in Outlook?
Yes. Copilot in Outlook requires an eligible Microsoft 365 or Copilot plan; for work accounts, a Microsoft 365 Copilot licence. Check Microsoft's pages or your IT team for your account.
What is the difference between Copilot in Outlook and AI Reply Writer?
Copilot is Microsoft's AI inside Outlook and Microsoft 365. AI Reply Writer is a browser extension with a reply button in Outlook on the web and in many other apps, with a free plan.
Does AI Reply Writer work in the Outlook desktop app?
No. It works in Outlook on the web — outlook.live.com and outlook.office.com — in your browser.
Is there a free alternative to Copilot for Outlook replies?
AI Reply Writer has a free plan with a monthly allowance of replies, and works in Outlook on the web.
