To sync an Outlook calendar with an iPhone, open Settings > Apps > Calendar > Calendar Accounts > Add Account > Outlook.com, sign in, and make sure Calendars is turned on for that account, as Microsoft's iPhone calendar guide describes (checked 29 October 2026). If you would rather keep Outlook separate from Apple's Calendar app, install the Outlook app for iPhone, sign in, and tick each calendar you want to see.
Add an Outlook.com account to the iPhone Calendar app
Adding Outlook.com through iOS Settings puts your Outlook calendars inside Apple's Calendar app next to iCloud, with no extra app. Microsoft's steps match the iOS 27 labels in Microsoft's iPhone calendar guide (checked 29 October 2026):
- Open Settings, scroll to Apps, and tap Calendar.
- Tap Calendar Accounts. If the Outlook account is already on the phone for Mail, tap it; otherwise tap Add Account.
- Choose Outlook.com and sign in with your Microsoft account.
- Back in the account list, open the Outlook account and turn on Calendars. Turn off Mail, Contacts or Notes if you only want the calendar.
- Open the Calendar app, tap Calendars at the bottom of the screen, and tick the Outlook calendars you want to see.
This route covers personal accounts that end in outlook.com, hotmail.com or live.com. Microsoft notes that support for this connection comes from Apple, because the account runs inside Apple's app. Once it is added, your Outlook calendars and their events appear in the Calendar app and its widgets, alongside any iCloud or Google calendars already on the phone. Adding the account does not move or merge anything, so removing it later removes only the Outlook calendars from the phone.
Add a work or school Microsoft 365 account
A work or school account on Microsoft 365 uses the Microsoft Exchange option instead of Outlook.com. Apple documents the setup in Set up Exchange ActiveSync on your iPhone (checked 29 October 2026):
- Open Settings, tap Apps, tap Mail, then tap Mail Accounts.
- Tap Add Account, then Microsoft Exchange, enter your work email address and tap Next.
- Tap Sign In so the iPhone finds your organisation's server, then sign in. Most Microsoft 365 tenants hand you to their own sign-in page at this point.
- Turn on Calendars, along with any of Mail, Contacts, Reminders and Notes you want, then tap Save.
Exchange accounts added this way show up under Calendar Accounts too, so the same account list controls both Mail and Calendar. Only use Configure Manually if your IT team has given you server details. Some organisations allow only the Outlook app on phones; if your sign-in is refused in the built-in app, the Outlook app route below is the one to use.
Use the Outlook app on iPhone instead
The Outlook app for iPhone shows your Outlook calendars inside Microsoft's own app, which suits work accounts with app-only policies and anyone who wants mail and calendar in one place. After you install it from the App Store and sign in, open the calendar view and its list of calendars. Microsoft's guidance in its phone and tablet sync article is to make sure each calendar you want under your account is ticked (checked 29 October 2026).
The same Microsoft page notes that accounts set up as IMAP or POP sync email only, never calendars, so add Outlook.com or Exchange accounts rather than a generic IMAP mailbox. Signing in to the Outlook app does not by itself add the account under Calendar Accounts in iOS Settings, so if you also want those events in Apple's Calendar app, add the account there as described above.
What adding Outlook to iPhone syncs, and what stays separate
Adding an Outlook account to the iPhone syncs that account in both directions. Events you create or edit on an Outlook calendar in the iPhone Calendar app write back to Outlook, and changes made in Outlook on the web or on a computer come down to the phone. That two-way sync stays inside the one account, though. Your iCloud calendar and your Outlook calendar sit side by side in the same app, but neither copies events into the other. A dentist appointment saved to iCloud never reaches Outlook, so colleagues checking your Outlook free/busy time still see you as available.
Because both accounts live in one app, new events go wherever the default points. Set it in Settings > Apps > Calendar > Default Calendar, per Apple's Calendar settings guide (checked 29 October 2026), and pick the Outlook calendar if most of what you add is work. When you create an event, you can still tap Calendar on the new-event screen to send that one event to a different account.
Copy Outlook busy time into iCloud, or the reverse
Showing Outlook and iCloud on one iPhone only stacks the two calendars on that phone. To make events from one account appear on the other account itself, so that Outlook free/busy, scheduling links and people who share your iCloud calendar all see the same busy time, it takes a sync service that copies events between the accounts. Keeper.sh, a managed calendar sync service, does this job for Outlook, Microsoft 365, iCloud, Google Calendar, Fastmail and CalDAV calendars.
Setup is three steps: connect the Outlook and iCloud accounts, choose which calendar receives the copies, and Keeper.sh keeps them in sync from then on. Each connection copies one way, so add a second connection in the opposite direction if you want iCloud events on Outlook and Outlook events on iCloud. Each copied event arrives as a busy block named after the source calendar, with the title, description and location hidden by default; Pro can show them again per calendar. Guest lists are never copied.
On the Free plan, with 2 accounts and 3 connections, changes land every 30 minutes. Keeper.sh Pro costs $5 a month or $45 a year and moves Outlook changes within seconds and updates iCloud calendars every minute. For the same job between iCloud and a Windows or web copy of Outlook, see how to sync iCloud Calendar with Outlook.
Related iPhone and Outlook calendar guides
Google accounts join the iPhone the same way through Calendar Accounts; how to add Google Calendar to iPhone walks through that route and the Google calendar picker. To link Google Calendar with Outlook, iCloud and other providers beyond the phone, start with how to sync Google Calendar with other calendars.
If the account is added but Outlook events never reach the phone, first confirm that Calendars is still turned on for the account under Calendar Accounts, then check Fetch New Data. If they are both set, our guide to Outlook calendar sync problems covers resyncing the account in each Outlook client.