Buy Microsoft 365 if you use Office regularly and want always-current apps plus 1 TB of OneDrive cloud storage — it's a subscription (~$69.99–$99.99/year) that never goes out of date. Buy Office 2021 if you want a one-time purchase (~$149.99) with no recurring cost and are fine using that version for years without new features. The decision is subscription-with-extras versus own-it-once simplicity.
The fundamental difference
Microsoft 365 is a subscription: you pay yearly (or monthly) and always have the latest version of Word, Excel, PowerPoint, Outlook and more, plus cloud extras — 1 TB of OneDrive storage per person and ongoing feature updates. Stop paying and the apps stop working.
Office 2021 is a perpetual license: one payment, one PC or Mac, that version forever. You keep it indefinitely with no further cost, but you get no new features — just security updates until its support window ends.
Side-by-side
| Microsoft 365 | Office 2021 | |
|---|---|---|
| Cost model | Subscription (~$69.99–$99.99/yr) | One-time (~$149.99) |
| Apps included | Word, Excel, PowerPoint, Outlook, + more | Word, Excel, PowerPoint, Outlook |
| Updates | Continuous new features | Security only, no new features |
| OneDrive storage | 1 TB per person | None |
| Devices | Multiple (Personal 1 / Family 6 users) | 1 PC or Mac |
| Stop paying | Apps stop working | Keep using forever |
Which one fits you
- Choose Microsoft 365 if you use Office weekly, work across devices, want cloud storage and collaboration, or share with a household (Family covers 6 people, each with 1 TB). Over 2+ years the always-current apps and OneDrive usually justify the subscription.
- Choose Office 2021 if you use Office occasionally, on one computer, dislike subscriptions, and are happy with the current feature set for the next several years.
The math
Office 2021 at ~$149.99 breaks even against Microsoft 365 Personal (~$69.99/yr) after roughly two years. If you'll use Office longer than that and don't need OneDrive or multi-device access, the one-time purchase is cheaper. If you value cloud storage and always-new features, the subscription wins — and Family is exceptional value for households.
