# Microsoft 365 vs OnlyOffice (2026)

By Noah — last updated & pricing verified September 14, 2026.

> **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.

**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

## At a glance

|  | Microsoft 365 | OnlyOffice |
| --- | --- | --- |
| Pricing | From $9.99/mo | Free tier · paid from $20/mo |
| License | Paid | Open core |
| 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 | organizations that need Microsoft Office-compatible editing but want the option to self-host on their own servers under an open-source license |
| Ratings | Capterra 4.6/5 (14,143 reviews) | Capterra 4.5/5 (324 reviews) |

## Feature comparison

| Feature | Microsoft 365 | OnlyOffice |
| --- | --- | --- |
| Starting price | Yes (from $9.99/mo (Personal, 1 person)) | Yes (free (Startup); paid Business Cloud from $20/admin/mo (unlimited users included)) |
| Free tier | No (no free tier, only a one-time-purchase alternative) | Yes (Startup plan free for up to 3 admins and unlimited users) |
| Pricing unit | Yes (priced per person (1-6 people per subscription)) | Yes (priced per admin, with unlimited regular users included free) |
| Open-source / self-hostable | No (closed-source, proprietary) | Yes (AGPL 3.0 source code, self-hostable) |
| One-time or perpetual free option | Yes (Office Home 2024, one-time $179.99, no Copilot, no future upgrades) | Yes (desktop editors and Community Server are free to self-host indefinitely) |
| Platforms | Partial (web, Windows, macOS, iOS, Android (no native Linux app)) | Yes (web, Windows, macOS, Linux, iOS, Android) |
| Storage (top standard tier) | Yes (1TB per person, up to 6TB pooled on Family/Premium) | Yes (250GB per admin on Business Cloud (2GB per space on free Startup)) |
| AI features | Yes (Copilot built into Word, Excel, PowerPoint, Outlook; AI agents on Premium ($19.99/mo)) | Yes (built-in AI assistants for content generation, translation, and scanned-document text extraction) |
| Format fidelity for complex documents | Yes (native format, no conversion needed) | Partial (reviewers report fidelity issues on complex documents with heavy macros or advanced layout) |
| Real-time co-editing detail | Unknown (real-time co-editing granularity not specified in our listing data) | Yes (character-level real-time change tracking) |
| Notable deployments / user base | Unknown (specific deployment examples not in our listing data) | Yes (deployments include UNESCO and the Red Cross; reports 21 million-plus users) |
| Third-party integrations | Unknown (specific integrations not listed in our listing data) | Yes (40+ integrations including Nextcloud and Moodle) |
| External rating | Yes (4.6/5 from 14,143 reviews (Capterra)) | Yes (4.5/5 from 324 reviews (Capterra)) |
| On-premises/enterprise deployment | No (cloud subscription only, no self-hosted option) | Yes (Enterprise 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

- Pro: Bundles full-featured desktop and web apps (Word, Excel, PowerPoint, Outlook, OneNote) in one subscription.
- Pro: Generous cloud storage — 1TB per person, up to 6TB pooled on Family and Premium.
- Pro: Copilot AI assistance is built into Word, Excel, PowerPoint, and Outlook rather than sold separately.
- Pro: Family and Premium plans cover up to 6 people under a single subscription.
- Con: No ongoing free tier; canceling the subscription removes access to the desktop apps entirely.
- Con: The only one-time-purchase option (Office Home 2024, $179.99) lacks Copilot and never gets feature upgrades.
- Con: Advanced Copilot AI agents require the $19.99/month Premium tier, a $10-20/month jump over Personal.
- Con: Reviewers cite setup and admin complexity, especially for business deployments.

### OnlyOffice

- Pro: AGPL 3.0 source code available on GitHub; fully self-hostable for organizations that need to keep data on-premises.
- Pro: DocSpace charges only for admin seats, with unlimited regular users invited free.
- Pro: Native apps across Windows, macOS, Linux, iOS, and Android, plus 40+ third-party integrations including Nextcloud and Moodle.
- Pro: Real-time co-editing with character-level change tracking and built-in AI content tools.
- Con: Complex documents with advanced Word/Excel formatting or macros can lose fidelity when opened in ONLYOFFICE.
- Con: Enterprise on-premises pricing is not published; requires a sales conversation.
- Con: Per-admin pricing model on Business Cloud takes more effort to compare against per-user competitors.
- Con: 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. |

## 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.

## Neither a match?

- 5 alternatives to Microsoft 365: https://findalternative.to/microsoft-365
- 5 alternatives to OnlyOffice: https://findalternative.to/onlyoffice

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