One Microsoft 365 licence can run the Office apps on several computers, tablets and phones, but the rules differ between home and work accounts, and the limit counts sign-ins rather than downloads. This guide explains what "5 devices" actually means, how to install on each device and how to free a slot when you replace one.
How many devices can I install Microsoft 365 on?
With Microsoft 365 for home, you can install the apps on all your devices and stay signed in on five at the same time, in any mix of PCs, Macs, tablets and phones; with a work or school licence, Microsoft allows five PCs or Macs, five tablets and five phones per user.
| Account type | Install limit | Active limit | How to free a slot |
|---|---|---|---|
| Microsoft 365 Personal or Family (per person) | All your devices | 5 signed-in devices at once, any type | Sign out on the device or from the Installs page of your Microsoft account |
| Work or school (Microsoft 365 Apps licence) | 5 PCs or Macs, 5 tablets, 5 phones | Per category, per user | Office portal, My Account device list or your admin |
| Shared computer activation (business) | One shared PC, many users | Does not count against the user limit | Configured by IT |
The source for these limits is Microsoft's own article on signing in to Microsoft 365, which has separate tabs for home and business plans. One nuance: on home plans, Microsoft signs you out of the oldest device automatically when you exceed five, so the limit rarely blocks you outright.
What does "5 devices" mean in Microsoft 365?
"5 devices" refers to how many devices can hold an active, signed-in copy of the Office apps under one user licence at the same time, not how many times you can download the installer; signing out of a device releases its place, and signing in on a new device uses one.
This is the key cause and effect behind most "too many devices" messages. Microsoft 365 activation lives in the signed-in account, so when you sign out, the licence is removed from that device and the apps drop to view and print only until you sign back in.
For Microsoft 365 Family, each person you share the subscription with uses their own account and gets their own five-device allowance. Sharing does not pool devices onto one account; every member signs in separately.
How do I install Microsoft 365 on another PC or Mac?
On the new computer, go to Microsoft's apps portal at m365.cloud.microsoft/apps, sign in with the account that holds your subscription, select Install apps, run the downloaded installer, and then open Word and sign in with the same account to activate the apps on that device.
- Open a browser on the new PC or Mac and go to m365.cloud.microsoft/apps.
- Sign in with your Microsoft account, or your work or school account.
- Select Install apps, then Microsoft 365 apps for a work account.
- Run the installer and approve the User Account Control prompt on Windows.
- Open Word or Excel and sign in with the same account to activate.
Microsoft installs the 64-bit version by default unless it detects a 32-bit Office or standalone Project or Visio already present, as its install guide explains. If an older one-time Office version is on the PC, remove it first using our guide to completely uninstalling old Office.
How do I install Microsoft 365 on a phone or tablet?
Install the Microsoft 365 app, or individual Word, Excel and PowerPoint apps, from the App Store or Google Play, open it, tap Sign In and use the same account as your subscription; the device then counts towards your limit, and on work plans phones and tablets have their own separate allowance of five each.
On iPhone and iPad, sign in from the Account screen of the app. On Android and Chromebooks, sign in from the Recent screen, as Microsoft describes for each platform.
What we commonly see is a user who installed the apps on a phone but never signed in, so the device appears to be using a slot when it is not. Only a signed-in installation counts, so check the account inside the app before assuming the limit is full.
How do I remove an old device from Microsoft 365?
Sign out of Office on the old device through File, Account, Sign out, or, if you no longer have the device, open the Installs page of your Microsoft account, find it under Devices and choose Sign out of Office; Microsoft says remote sign-out can take up to 72 hours to take effect.
Signing out does not uninstall Office, delete documents or cancel your subscription. It only removes that device's licence, and Microsoft's article on signing out of Office lists the steps for PC, Mac and mobile apps.
For a work or school account, Microsoft directs users to the Office portal account page, where Apps and devices lists each installation with a Sign out option. Your organisation's admin can also remove unused devices if the list does not update.
What happens if I go over the device limit?
On Microsoft 365 for home, Office signs you out of devices automatically to stay within five, so the oldest session simply needs a fresh sign-in later; on work plans, the newest activation can fail with a message that the maximum number of devices is reached until an unused device is removed.
Microsoft's licensing overview for Microsoft 365 Apps adds that if a user installs on more than 10 devices, the device not used for the longest time is deactivated automatically. Microsoft notes this automatic deactivation currently works for Windows devices only.
A deactivated device enters reduced functionality mode. Files stay on the device and can be viewed and printed, but editing and creating documents are disabled until you sign in again.
Do Microsoft 365 apps need to go online to stay activated?
Yes, periodically: Microsoft 365 Apps check the licence with Microsoft's activation service regularly, and as long as the device connects to the internet at least once every 30 days the apps remain fully functional; a device offline for longer enters reduced functionality mode until it reconnects.
This is the main practical difference from one-time-purchase editions such as Office 2024 or Office LTSC 2024, which activate once and do not need a regular check-in. Microsoft itself recommends Office LTSC for computers that are completely cut off from the internet.
If your work involves long periods offline, compare the options in our guide to Office 2024 vs Office 2021, or look at the Office 2024 collection for one-time licences.
What is shared computer activation?
Shared computer activation is a business licensing mode where Microsoft 365 Apps are installed once on a computer used by several people, such as a Remote Desktop Services server or a shift-work PC, and each person signs in with their own licensed account; Microsoft states it does not count against a user's normal device limit.
Microsoft's shared computer activation overview lists eligible plans: those including Microsoft 365 Apps for enterprise, plans with desktop Project or Visio, and Microsoft 365 Business Premium. Business Standard is not eligible, and the feature is not available for Office on Mac.
It is an IT-managed setting, enabled with the Office Deployment Tool or Group Policy, not something a home user switches on. If you run an RDS server, our guide to setting up Remote Desktop Services covers the server side.
How much OneDrive storage comes with Microsoft 365?
OneDrive storage depends on the specific Microsoft 365 plan and account type rather than on the number of devices, so check the plan details shown in your Microsoft account or admin centre; storage is attached to each user's account and is shared across every device that user signs in on.
Installing the apps on a fifth device does not add or reduce storage. Files saved to OneDrive appear on all signed-in devices, which is often the main reason people install on several machines in the first place.
Some sellers offer Microsoft 365 accounts sold as one-off purchases rather than renewing subscriptions. Before buying one, read our explainer on how "lifetime" Office 365 accounts work, so you understand who controls the account and what happens to your files if the arrangement ends.
Frequently asked questions
Can I install Microsoft 365 on more than five devices?
On home plans you can install on as many devices as you like, but only five can be signed in at the same time. On work plans, each user can activate on five PCs or Macs, five tablets and five phones. Signing out of an unused device frees its place.
Does reinstalling Windows use another device slot?
It can, so sign out of Office before wiping the PC where possible. If you forgot, open the Installs page of your Microsoft account and sign out the old entry, or on home plans let Office sign out the oldest device automatically when you pass the five-device limit.
Can two people use one Microsoft 365 Personal account?
Microsoft 365 Personal is for one person. To cover several people, Microsoft 365 Family lets the owner share with up to five others, each using their own Microsoft account and their own device allowance. Sharing one sign-in between people is not how the plan is designed.
Why does Office still say Unlicensed Product after I signed in?
The signed-in account may not hold the subscription, the subscription may have expired, or an older Office version may be competing for the licence. Check Services and subscriptions in your Microsoft account, then follow our guide to fixing Unlicensed Product in Office.
Can I use Microsoft 365 on a Mac and a Windows PC at the same time?
Yes. Microsoft 365 licences cover both Windows and macOS, and a Mac counts as one of your devices in the same way as a PC. Sign in with the same account on each computer, and your OneDrive files and settings follow you between them.