Most people looking for a free Microsoft Office alternative land on LibreOffice first, but it isn't the only serious option. OnlyOffice is a free, open-source office suite (the desktop editors are free; there are separate paid cloud/server products aimed at businesses) that was built from the ground up around Microsoft's file formats, rather than treating .docx and .xlsx as something to convert. That design choice shows in day-to-day use.
Key takeaway: OnlyOffice Desktop Editors are free, look almost identical to modern Microsoft Office, and offer noticeably better fidelity with .docx/.xlsx/.pptx files than most alternatives — at the cost of a smaller feature set for advanced spreadsheet work.
Why compatibility feels different here
LibreOffice's native formats are the open ODF standard (.odt, .ods, .odp), with Microsoft format support layered on as an import/export feature. OnlyOffice took the opposite approach: its editors use Office Open XML (the .docx/.xlsx/.pptx family) as their native working format. In practice, this means documents that round-trip between OnlyOffice and Microsoft Word tend to keep their layout, spacing and formatting more reliably, since there's no format conversion happening behind the scenes.
The interface
OnlyOffice's Ribbon-based interface will feel instantly familiar to anyone who has used Word, Excel or PowerPoint in the last decade — tabs for Home, Insert, Layout, References and so on, in roughly the same places. This is a real advantage for anyone switching from Microsoft Office who doesn't want to relearn menu structures, particularly older or less tech-confident users in the household.
Tip: If a family member is nervous about switching away from "real" Office, start them on OnlyOffice rather than LibreOffice — the visual similarity to Word reduces the learning curve considerably.
Where it falls short
OnlyOffice's spreadsheet editor, while solid for budgets, invoices and everyday formulas, has a smaller library of advanced functions and chart types than either Excel or LibreOffice Calc, and pivot table support is more basic. It also lacks a dedicated database tool (LibreOffice has Base) and its macro/scripting support is less mature than either rival. For document and presentation work, though, it holds up very well.
Getting started
- Visit the official onlyoffice.com site and download "Desktop Editors" — the free, offline version (not the cloud/enterprise products, which are paid).
- Install it as you would any Windows or macOS application; no account or sign-up is required for local use.
- Open the app and use the built-in file browser to open .docx, .xlsx or .pptx files from your computer, or drag files directly onto the launch screen.
- Set OnlyOffice's default save format under the application settings if you want it to keep files in Microsoft format automatically.
- Optionally connect a cloud storage account (Nextcloud, ownCloud, or OnlyOffice's own free-tier cloud) if you want documents to sync between devices.
| Factor | OnlyOffice | LibreOffice |
|---|---|---|
| Microsoft format fidelity | Excellent | Very good |
| Interface familiarity (Ribbon) | Very close to Word/Excel | Traditional menus (Ribbon optional) |
| Advanced spreadsheet functions | Good, fewer than Excel | Strong, closer to Excel |
| Database tool included | No | Yes (Base) |
| Cost | Free (desktop editors) | Free |
Before you start: download only from onlyoffice.com. Be careful not to accidentally sign up for a paid cloud plan when you only want the free desktop editors — the download page separates them clearly, but read before clicking.
Verdict
If your priority is a free suite that behaves as closely as possible to modern Microsoft Word and Excel, OnlyOffice is arguably the better match. If you want the broadest feature set, including a database tool and deeper spreadsheet functions, LibreOffice edges ahead. Both are entirely free for home use and there's no harm in installing both to see which fits your workflow.
Frequently asked questions
- Is OnlyOffice completely free for personal use?
- Yes, the Desktop Editors are free and open source under an AGPL licence. OnlyOffice also sells separate cloud and business server products, but you don't need them for offline personal use.
- Can OnlyOffice open LibreOffice's .odt files?
- Yes, OnlyOffice can open and export ODF formats, though its primary strength remains Microsoft format compatibility.
- Does OnlyOffice work without an internet connection?
- Yes, the desktop editors run entirely offline once installed; an internet connection is only needed if you choose to connect a cloud storage service.