Replace your Microsoft 365 subscription with these 5 free open-source apps
Microsoft 365 is not the only suite available and does not have the best tools on the market. However, many professionals, students and casual users are totally connected to it. However, before you commit to another payment cycle, it’s a good idea to pump the brakes and seriously consider alternatives that are free, open source, and may work better.
The digital world is full of amazing applications created and maintained by global communities focused on creating powerful and accessible tools. Taking the time to explore this alternative landscape can prove that it’s entirely possible to continue working exactly as you’re used to, without paying the price.
Word replacement – LibreOffice Writer
LibreOffice Writer is the best open source word processor you can get as a Word replacement. When I first switched, LibreOffice looked almost identical to Word. Although both interfaces have been updated and diverged slightly over the years, the main workflow remains the same. Additionally, Writer has a tabbed user interface that mimics the ribbon layout in Microsoft Office.
Word formatting is incredibly frustrating, often causing difficult-to-fix layout errors. Writer relies on a highly structured style system that ensures that your documents remain completely stable. Unlike standard word processors, in which manual formatting replaces document structure, this structured system uses five style categories: paragraph, character, frame, page, and list. Writer shifts the focus from physical attributes (what the text looks like) to logical attributes (what the text actually is).
I was convinced by this program from the moment I started it for the first time. You don’t feel like you’ve left the Microsoft ecosystem, and yet you suddenly have tools that Word simply lacks. It’s easily one of the best open source applications to replace Word.
Excel Replacement – Gnumeric
Many people think that commercial software has become too demanding on system resources, and if you need pure speed and guaranteed mathematical integrity without all the unnecessary overhead, Gnumeric is definitely your best choice. It removes the extra interface elements and background processes that often slow down paid programs, giving you a streamlined environment dedicated strictly to crunching the numbers.
It is well known for being much more accurate than Excel when doing advanced statistical work. Moving away from the Microsoft ecosystem is often hampered by the fear of losing core features, but Gnumeric handles this gap brilliantly. It actually includes all Excel spreadsheet functions, ensuring compatibility with your current files and workflows.
However, it doesn’t just copy old standards; You also get 154 unique features unavailable in the Microsoft ecosystem, which are incredibly useful if you work in telecommunications engineering or financial derivatives. Although LibreOffice Calc’s standard features may seem simple, the specific rigor provided by Gnumeric puts it ahead of other open source alternatives for Excel.
Outlook Replacement – Mozilla Thunderbird
Thunderbird is a great alternative when you see how the landscape is dominated by tech giants hungry for your personal data. Thunderbird has always been user-focused in this regard, and its interface has a cleaner look and a better folder pane. This app proves that open source tools can absolutely rival the refinement you find in software like Outlook, while still maintaining the flexibility you actually need.
You can easily merge inboxes from ten different accounts into one clear view. This lets you manage everything from Gmail to corporate Exchange right next to each other without any friction. This setup also streamlines file management, so you can drag emails from a corporate server directly to your local folders for offline archiving and backup.
You can do all this while keeping your privacy completely locked down locally. Unlike the “New Outlook” for Windows 11, which uploads IMAP credentials and data to Microsoft’s cloud regardless of your email provider, Thunderbird ensures your data stays directly on your device. This means that your personal communications are not analyzed for advertising profiles or by a remote service provider.
OneDrive Replacement – Proton Drive
Proton is the gold standard in end-to-end encrypted cloud storage. With something like OneDrive, Microsoft pretty much holds the keys, meaning it can technically scan your content whenever it wants for compliance reasons. As we noted in our Proton Drive review, it encrypts everything locally before it even touches the servers. This is huge because it means that Proton itself cannot see your file names or the contents of your files.
The company significantly improved its sync speed for Windows and macOS apps starting in early 2026 with the rollout of C# and JavaScript SDKs. This architectural difference is absolutely essential if you are serious about a true digital property.
When you move to Proton Drive, you’re effectively moving your digital life to Switzerland, taking advantage of some of the strictest privacy laws in the world to protect your information from surveillance and accidental data breaches. Additionally, the service is open source. This means that external security researchers can inspect the code to confirm that the encryption works exactly as the company claims.
OneNote Replacement – Joplin
If you’re serious about note-taking, Joplin is absolutely the way to go and is also a good replacement for your web applications. It ditches that messy, free-form canvas that makes OneNote so awkward and instead gives you a structured, fast system. It uses Markdown, and that’s essential because your notes are just simple plain text files. This makes them scalable because you can read and write on them easily, and that will probably be true in 50 years.
Web Clipper is better than OneNote, allowing you to clip entire web pages into clean, editable notes. You don’t need to constantly fiddle with formatting toolbars or alignment settings, allowing you to stay in your flow state without having to deal with a complex user interface. It also removes ads, sidebars, and broken layouts to give you a readable format that requires no cleanup, unlike the often messy clips you get from competitors.
The app is highly customizable with an organized plugin system, so you can easily add features like Kanban boards or advanced links without slowing down or overwhelming the main app.
When we look at free and open source options versus proprietary ecosystems like Microsoft 365, it’s clear that the difference is more than just a price tag. You’re preparing for a future where your tools are flexible, your files are private by default, and your entire workflow isn’t dictated by a company’s product roadmap or a sudden price hike.
The functionality, innovation, and ethical foundation of these free apps prove that you don’t need an expensive paywall to get premium or enterprise-grade features. All it takes is the willingness to try something new.
