Microsoft 365 vs OnlyOffice (2026)
By Noahlast updated
Verdict: Choose Microsoft 365 if you want native Word, Excel, PowerPoint, and Outlook with guaranteed formatting fidelity, generous per-person cloud storage, and Copilot AI built into every app from $9.99/month. Choose OnlyOffice if you want AGPL 3.0 open-source software you can self-host, with Business Cloud charging only for admin seats ($20/admin/month) while unlimited regular users join free. The deciding factor is licensing and pricing structure: Microsoft 365 is a closed-source, per-person subscription with no self-hosting option, while OnlyOffice is self-hostable and open-source but reviewers report formatting fidelity issues on complex documents with heavy macros.
Microsoft 365
Microsoft 365Subscription bundle of Word, Excel, PowerPoint, Outlook, and OneDrive storage with Copilot AI, starting at $9.99/month.
- Pricing
- From $9.99/mo
- License
- Paid
- Best for
- individuals and families who want the full desktop-grade Office apps plus generous cloud storage and Copilot AI synced across multiple devices, rather than free browser-only Office
OnlyOffice
OnlyOfficeAn open-source office suite (AGPL 3.0) for editing documents, spreadsheets, and presentations, with a self-hosted DocSpace collaboration platform priced per admin, not per user.
- Pricing
- Free tier · paid from $20/mo
- License
- Open core
- Best for
- organizations that need Microsoft Office-compatible editing but want the option to self-host on their own servers under an open-source license
Choose Microsoft 365 if…
- You want native Word, Excel, PowerPoint, and Outlook with guaranteed full formatting fidelity, not a compatible alternative
- You want generous per-person cloud storage (1TB, up to 6TB pooled on Family/Premium) bundled with the apps
- You want Copilot AI built into every core app without configuring a separate self-hosted AI tool
- You're comparing on review volume and want the platform with a much larger public review base (14,143 vs 324 reviews)
Choose OnlyOffice if…
- You want to self-host on your own servers under an open-source AGPL 3.0 license instead of a closed-source cloud subscription
- You have many regular users but few admins, since Business Cloud charges only for admin seats and includes unlimited users free
- You want a permanently free option beyond a one-time purchase, since OnlyOffice's desktop editors and Community Server are free to self-host indefinitely
- You need a native Linux desktop client, which Microsoft 365 doesn't offer
- You can tolerate occasional formatting fidelity issues on complex documents with heavy macros in exchange for self-hosting control
Microsoft 365 vs OnlyOffice: feature comparison
| Feature | Microsoft 365 | OnlyOffice |
|---|---|---|
| Starting price | Yesfrom $9.99/mo (Personal, 1 person) | Yesfree (Startup); paid Business Cloud from $20/admin/mo (unlimited users included) |
| Free tier | Nono free tier, only a one-time-purchase alternative | YesStartup plan free for up to 3 admins and unlimited users |
| Pricing unit | Yespriced per person (1-6 people per subscription) | Yespriced per admin, with unlimited regular users included free |
| Open-source / self-hostable | Noclosed-source, proprietary | YesAGPL 3.0 source code, self-hostable |
| One-time or perpetual free option | YesOffice Home 2024, one-time $179.99, no Copilot, no future upgrades | Yesdesktop editors and Community Server are free to self-host indefinitely |
| Platforms | Partialweb, Windows, macOS, iOS, Android (no native Linux app) | Yesweb, Windows, macOS, Linux, iOS, Android |
| Storage (top standard tier) | Yes1TB per person, up to 6TB pooled on Family/Premium | Yes250GB per admin on Business Cloud (2GB per space on free Startup) |
| AI features | YesCopilot built into Word, Excel, PowerPoint, Outlook; AI agents on Premium ($19.99/mo) | Yesbuilt-in AI assistants for content generation, translation, and scanned-document text extraction |
| Format fidelity for complex documents | Yesnative format, no conversion needed | Partialreviewers report fidelity issues on complex documents with heavy macros or advanced layout |
| Real-time co-editing detail | Unknownreal-time co-editing granularity not specified in our listing data | Yescharacter-level real-time change tracking |
| Notable deployments / user base | Unknownspecific deployment examples not in our listing data | Yesdeployments include UNESCO and the Red Cross; reports 21 million-plus users |
| Third-party integrations | Unknownspecific integrations not listed in our listing data | Yes40+ integrations including Nextcloud and Moodle |
| External rating | Yes4.6/5 from 14,143 reviews (Capterra) | Yes4.5/5 from 324 reviews (Capterra) |
| On-premises/enterprise deployment | Nocloud subscription only, no self-hosted option | YesEnterprise on-premises deployment, custom pricing per connection |
Can OnlyOffice open Microsoft Word and Excel files?
Yes, but reviewers report that complex documents with advanced formatting or macros can lose fidelity when opened in OnlyOffice.
Is OnlyOffice really free?
Yes for smaller teams — OnlyOffice's Startup DocSpace plan is free for up to 3 admins with unlimited users, and its desktop editors and Community Server can be self-hosted indefinitely at no cost.
Business Cloud, the paid DocSpace tier, costs $20/admin/month (discounted from $30) but still includes unlimited regular users free, unlike Microsoft 365's per-person pricing where every user needs a paid seat. Microsoft 365 has no permanently free tier at all — the only non-subscription option is the one-time $179.99 Office Home 2024 purchase, which excludes Copilot and never receives feature upgrades.
Which has more cloud storage, Microsoft 365 or OnlyOffice?
Microsoft 365 offers more per-person storage — 1TB per person, up to 6TB pooled on Family and Premium — versus OnlyOffice Business Cloud's 250GB per admin.
Can I self-host OnlyOffice instead of using the cloud version?
Yes — OnlyOffice's Community Server is free to self-host, and Enterprise on-premises deployment is available with custom per-connection pricing, options Microsoft 365 doesn't offer since it's cloud-subscription only.
Strengths and weaknesses
Microsoft 365
Pros
- Bundles full-featured desktop and web apps (Word, Excel, PowerPoint, Outlook, OneNote) in one subscription.
- Generous cloud storage — 1TB per person, up to 6TB pooled on Family and Premium.
- Copilot AI assistance is built into Word, Excel, PowerPoint, and Outlook rather than sold separately.
- Family and Premium plans cover up to 6 people under a single subscription.
Cons
- No ongoing free tier; canceling the subscription removes access to the desktop apps entirely.
- The only one-time-purchase option (Office Home 2024, $179.99) lacks Copilot and never gets feature upgrades.
- Advanced Copilot AI agents require the $19.99/month Premium tier, a $10-20/month jump over Personal.
- Reviewers cite setup and admin complexity, especially for business deployments.
OnlyOffice
Pros
- AGPL 3.0 source code available on GitHub; fully self-hostable for organizations that need to keep data on-premises.
- DocSpace charges only for admin seats, with unlimited regular users invited free.
- Native apps across Windows, macOS, Linux, iOS, and Android, plus 40+ third-party integrations including Nextcloud and Moodle.
- Real-time co-editing with character-level change tracking and built-in AI content tools.
Cons
- Complex documents with advanced Word/Excel formatting or macros can lose fidelity when opened in ONLYOFFICE.
- Enterprise on-premises pricing is not published; requires a sales conversation.
- Per-admin pricing model on Business Cloud takes more effort to compare against per-user competitors.
- DocSpace's interface is less polished than Google Workspace or Notion for non-technical teams.
Which fits your use case?
| Use case | Pick | Why |
|---|---|---|
| Business that wants full native Office apps with guaranteed formatting fidelity | Microsoft 365 | Microsoft 365 is the native format; OnlyOffice reviewers report fidelity issues on complex documents with heavy macros. |
| Organization that needs to keep documents on its own servers | OnlyOffice | OnlyOffice is AGPL 3.0 and self-hostable, including a free Community Server and custom-priced Enterprise on-premises deployment; Microsoft 365 is cloud-subscription only. |
| Team with many regular users but few admins on a budget | OnlyOffice | OnlyOffice Business Cloud charges only $20/admin/month with unlimited users included free, versus Microsoft 365's per-person pricing. |
| Family wanting generous shared cloud storage across up to 6 people | Microsoft 365 | Microsoft 365 Family pools up to 6TB (1TB per person) versus OnlyOffice's per-admin storage model, which isn't built for individual family storage pooling. |
| Organization needing an open-source suite auditable on GitHub | OnlyOffice | OnlyOffice publishes its source under AGPL 3.0; Microsoft 365 is closed-source. |
Neither a match?
Both lists carry verified pricing and honest weaknesses for every option.
Popular comparisons
Microsoft 365 vs OnlyOffice: migration FAQ
Should I use Microsoft 365 or OnlyOffice?
- Use Microsoft 365 for native Office apps with guaranteed formatting fidelity and generous per-person storage; use OnlyOffice if you want open-source, self-hostable software or many users under few paid admin seats.
Is there a free alternative to Microsoft 365?
- OnlyOffice's Startup DocSpace plan is free for up to 3 admins with unlimited users, and its desktop editors and Community Server can be self-hosted at no cost indefinitely, unlike Microsoft 365, which has no ongoing free tier.
Can OnlyOffice replace Microsoft 365?
- For most day-to-day editing, yes, but reviewers report that complex documents with advanced formatting or macros can lose fidelity when opened in OnlyOffice.
Is OnlyOffice open source?
- Yes — OnlyOffice is distributed under the AGPL 3.0 license with source code on GitHub and is fully self-hostable; Microsoft 365 is closed-source.
Which is cheaper for a team with many users, Microsoft 365 or OnlyOffice?
- OnlyOffice, since Business Cloud charges only $20/admin/month with unlimited regular users included free, while Microsoft 365 charges per person regardless of role.