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Office 2021, PC Guides
Can You Use Office 2021 on Multiple PCs?
A standard Office 2021 Professional Plus key licenses one PC. That’s the honest answer. But there are legitimate ways to cover multiple computers — MAK volume keys for businesses deploying across a fleet, and Microsoft 365 subscriptions for individuals who need Office on several devices. This guide covers all of them.
What the license actually covers
Office 2021 Professional Plus is sold as a per-device license. Microsoft’s terms allow installation and activation on one physical PC. The license does not follow the user — it follows the machine. This means:
- You cannot install the same key on your work PC and home PC simultaneously
- You cannot share one key across a team of employees
- Activating on a second machine after the first will either fail or deactivate the first
Option 1 — MAK keys for businesses (5 to 5,000 PCs)
Office 2021 Professional Plus MAK (Multiple Activation Key) keys are volume licenses that cover a set number of activations from a single key. Each machine that activates consumes one count from the pool. This is the correct solution for any business deploying Office across multiple machines.
| MAK tier | Activations included | Best for |
|---|---|---|
| Starter | 5 | Small office, home office with multiple machines |
| Small business | 50 | SMB deploying Office across a team |
| Mid-size | 100–500 | Growing company, MSPs managing client fleets |
| Enterprise | 1,000–5,000 | Large organizations, enterprise-wide Office rollouts |
MAK keys activate via Microsoft’s servers the same way a standard key does — using ospp.vbs /inpkey and /act via the command line, or through Office’s built-in activation dialog. For deployments of 50+ machines, Microsoft’s Volume Activation Management Tool (VAMT) lets you manage and track activations centrally.
Option 2 — Microsoft 365 for personal multi-device use
If you’re an individual who wants Office on multiple devices for personal use — laptop, desktop, tablet — Microsoft 365 is designed exactly for this:
- Microsoft 365 Personal ($69.99/year): 1 user, up to 5 devices simultaneously (PC, Mac, tablet, phone)
- Microsoft 365 Family ($99.99/year): Up to 6 users, 5 devices each
The trade-off: it’s a subscription that stops working if you cancel, and the per-year cost adds up significantly over time. See our full breakdown: Office 2021 vs Microsoft 365: Which Should You Buy?
Can you install Office 2021 on a second PC after upgrading?
A standard Office 2021 Retail license is a per-device license — it does not transfer the way Windows Retail keys do. If you get a new PC, you would need a new Office license for it. The old machine’s activation remains in place.
This is different from Windows 11 Pro Retail, which is transferable. Office perpetual licenses (2021, 2024) follow the device, not the user.
Single key vs multiple keys vs MAK — comparison
| 1 × Retail key per PC | MAK key (multi-seat) | Microsoft 365 | |
|---|---|---|---|
| Keys to manage | One per machine | One key, all machines | One subscription |
| Cost for 10 PCs | 10× single key price | Lower per-seat cost at volume | $69.99–$150/yr ongoing |
| Perpetual license | ✓ Yes | ✓ Yes | ✗ Subscription |
| Centralized management | ✗ | ✓ Via VAMT | Via admin portal |
| Best for | 1–4 machines | 5+ business machines | Personal multi-device |