LibreOffice vs OnlyOffice 2025: The Ultimate Comparison for Linux Users

For Linux users, the choice of an office suite usually comes down to two heavyweights: LibreOffice and OnlyOffice. While both allow you to write documents, analyze spreadsheets, and create presentations, their underlying engineering philosophies are radically different.

As an engineer running a multi-boot setup (Fedora, Debian, Windows 11), I need an office suite that doesn’t just “work,” but one that handles complex formatting without destroying my colleagues’ .docx files.

I tested the latest stable builds—LibreOffice 25.8 and OnlyOffice 8.2—on my Lenovo ThinkPad P14s G5 (Intel Ultra 7, 32GB RAM) to give you a definitive answer based on performance, compatibility, and architecture.

1. Architecture and Engine: The Core Difference

To understand the difference, we must look under the hood.

LibreOffice:

• Engine: Built on a decades-old C++ codebase (forked from OpenOffice). It uses traditional widget toolkits (GTK/Qt) to render the interface.

• Native Format: OpenDocument Format (.odt, .ods).

• Philosophy: Functionality first, offline-first, strict adherence to open standards.

OnlyOffice:

• Engine: Built using HTML5 and the <canvas> element. Essentially, the desktop app is a specialized web browser wrapper (similar to Electron, but highly optimized).

• Native Format: OOXML (.docx, .xlsx).

• Philosophy: Pixel-perfect Microsoft Office compatibility, cloud-first, visual consistency.

Engineering Insight: Because OnlyOffice uses the HTML5 Canvas, it renders fonts and layouts identically on Windows, Linux, and macOS. LibreOffice relies on system fonts and rendering libraries, which can sometimes lead to slight shifts in layout when moving files between OSs.

2. Microsoft Office Compatibility (OOXML)

This is the #1 deciding factor for most users.

OnlyOffice (The Winner):

During my testing with a complex 50-page corporate report containing floating tables and smart art, OnlyOffice rendered the file 99% identically to Microsoft Word. Since OnlyOffice uses .docx as its internal core format, there is no conversion process. What you see is what you get.

LibreOffice (The Runner Up):

LibreOffice 25.8 has made massive strides in compatibility. It opens .docx files much better than previous versions. However, on my test documents, I still noticed occasional issues:

• Floating images shifting slightly to the next page.

• Complex Excel macros requiring re-work.

• PowerPoint animations not playing smoothly.

Verdict: If you collaborate daily with Windows/Mac users running MS Office, OnlyOffice is the safer engineering choice.

3. Performance and Resource Usage

I ran both suites on my Fedora 43 workstation to measure system impact.

Startup Time (Cold Boot):

• LibreOffice: ~1.2 seconds (Incredibly fast, thanks to C++).

• OnlyOffice: ~3.5 seconds (Needs to load the web engine core).

RAM Usage (Blank Document):

• LibreOffice: ~180 MB

• OnlyOffice: ~350 MB

While OnlyOffice is heavier, on a modern machine with 16GB or 32GB of RAM (like my ThinkPad), this difference is negligible. However, if you are optimizing an older laptop with 8GB RAM, LibreOffice is lighter.

4. User Interface and Customization

LibreOffice:

It offers extreme modularity. By default, it uses the classic toolbar, but you can switch to the “NotebookBar” (Ribbon style) via View > User Interface.

• Pros: highly customizable, integrates with system themes (GTK4/LibAdwaita).

• Cons: Can look cluttered; menus are deep and complex.

OnlyOffice:

It looks almost exactly like Microsoft Office 2019/2021.

• Pros: Clean, modern, familiar tabs (File, Home, Insert).

• Cons: Very static. You cannot customize the interface deeply because it is drawn on a canvas, not using native Linux window elements.

5. Installation: Getting the Best Version

Fedora usually ships with LibreOffice, but for OnlyOffice, you need to install it manually.

How to Install LibreOffice (Latest):

If you want the absolute freshest version (standard repos might be a month behind), use Flatpak:

flatpak install flathub org.libreoffice.LibreOffice

How to Install OnlyOffice (Recommended Method):

I strictly recommend using the Flatpak version for OnlyOffice to ensure all dependencies (fonts, libraries) are bundled and isolated.

flatpak install flathub org.onlyoffice.desktopeditors

Note: Using the Flatpak ensures that the HTML5 renderer doesn’t conflict with your system’s web libraries.

6. Comparison Summary Table

Which One Should You Choose?

After extensive testing on the ThinkPad P14s, my recommendation depends on your workflow:

Choose LibreOffice if:

• You prioritize open-source purity and the .odt format.

• You work with massive spreadsheets (Calc is still more powerful than OnlyOffice Spreadsheet for raw data processing).

• You are on older hardware where every MB of RAM counts.

Choose OnlyOffice if:

• You receive .docx or .xlsx files from colleagues and need to send them back without formatting errors.

• You prefer the clean look of Microsoft Office.

• You use the cloud version (OnlyOffice DocSpace) for collaboration.

You may also read: Save Money in 2025: 5 Open Source Apps That Replaced Paid Software in My Workflow

My Personal Setup:

I keep both installed. I use LibreOffice for my personal engineering logs and CSV data crunching, but I switch to OnlyOffice instantly whenever I need to edit a document sent by a client using Word.