Do You Need Outlook on a Mac? Free Email Apps for Microsoft 365 Compared

If your business uses Microsoft 365, Outlook is not the only way to read your work email on a Mac. Apple Mail is already on every Mac, Outlook on the web comes with every business plan, and Thunderbird is free to download. All three can save money. The real question is what each one leaves out.

Is Outlook for Mac free?

Partly. Outlook for Mac is free to download, and it is free to use with personal accounts such as Gmail and iCloud. A Microsoft 365 work account is different. To sign in to the Outlook app with your work email, your plan needs to include the desktop apps.

Microsoft 365 Business Basic gives you the web and mobile versions only, so staff on Business Basic cannot use the Outlook app on their Mac. That is usually why businesses start looking at free alternatives. Our guide to choosing a Microsoft 365 plan for a Mac-based business explains what each plan includes.

Apple Mail and Calendar

Apple Mail and Calendar are free, already installed and familiar to most Mac users. With a Microsoft 365 account, Calendar handles the everyday work well. You can send and accept meeting invitations, see when colleagues are free, keep private appointments, set up repeating events and share your calendar with someone who manages it for you.

Where Apple Mail falls short is anything shared. Microsoft 365 shared mailboxes, such as an accounts or info address, are not officially supported in Apple Mail. There are workarounds that sometimes get one working, but they can stop working without warning, which is not something a business should rely on. You also cannot give a colleague access to your email so they can read and reply on your behalf. Both of those are set up and used in Outlook.

Right now, Apple Mail and Calendar on a Mac also have a sync problem with Microsoft 365 accounts, which Apple is fixing in a future macOS 27 update. Our guide to Outlook not syncing on a Mac covers what to do in the meantime.

Outlook on the web

Every Microsoft 365 business plan, including Business Basic, includes Outlook on the web. It is the same mailbox and calendar, opened in Safari or another browser, with nothing to install. It is also the simplest way for someone on Business Basic to use the Outlook features Apple Mail does not have.

The trade-off is that it lives in a browser tab rather than in its own app. For someone who checks email now and then, that is fine. For someone who works in their inbox all day, it can feel less convenient.

Thunderbird

Thunderbird is a free email app that now connects directly to Microsoft 365. When you add your work account, choose the Microsoft Graph option it offers, and keep the app up to date.

At the moment it handles email only. Your Microsoft 365 calendar and contacts do not appear in it yet, so you would still need another app for your calendar. It suits someone who wants a free alternative to Apple Mail for email, rather than a full replacement for Outlook.

What Outlook still does best

Outlook brings email, calendar and contacts together in one app, with the shared features a team relies on. You can open a shared mailbox alongside your own, and give a colleague access to your email, calendar and contacts with the level of control you choose, from read only to full editing. If your team uses Outlook on their iPhones as well, it is the same experience on every device.

If you already use Outlook for Mac, make sure you are on the current version. Since October 2026, the older version, known as legacy Outlook, no longer works with Microsoft 365 email. If your Outlook shows a Legacy Outlook switch, turn it off to move to the current version.

How to choose

If you work on your own, or your team does not share inboxes, Apple Mail and Calendar are a sensible free choice once Apple’s fix arrives. Keep Outlook on the web for the occasional task Apple Mail cannot do.

If your team shares an accounts or info inbox, or someone manages another person’s email and calendar, use Outlook. That means a Microsoft 365 plan that includes the desktop apps for those staff. We also cover adding a shared mailbox to Outlook on iPhone or iPad.

Thunderbird is a good option for anyone who only needs email and prefers it to Apple Mail.

Need a hand?

If you would like help choosing the right email setup for your team, or moving your Macs to it, see our Microsoft 365 & Email service, or contact Your Mac Tech.