Comparison of Office 365 and Thunderbird – Which one is the best email client for your business?

In today’s digital age, having the right office software is essential for productivity and efficiency. Two popular options for office productivity software are Office 365 and Thunderbird. Both offer a range of features and tools to meet the needs of individuals and businesses.

Office 365, developed by Microsoft, is a comprehensive suite of productivity tools that include Word, Excel, PowerPoint, Outlook, and more. It offers a wide range of features and integration with other Microsoft products, such as OneDrive and SharePoint. With Office 365, users can collaborate on documents in real-time, access their files from anywhere, and enjoy regular software updates.

On the other hand, Thunderbird is a free and open-source email client developed by Mozilla. While it may not have all the features of Office 365, it is a reliable and secure option for managing emails. Thunderbird supports multiple email accounts, has a customizable interface, and offers advanced security features like phishing protection and encryption.

So, when it comes to choosing between Office 365 and Thunderbird, it ultimately depends on your specific needs and priorities. If you require a comprehensive suite of office productivity tools with extensive features and integration, Office 365 is the way to go. However, if you mainly need a reliable and secure email client, Thunderbird is a great option that won’t cost you a dime.

Feature Comparison

When comparing Office 365 and Thunderbird, it’s important to consider the features that each software offers. Here is a breakdown of the key features of both:

Office 365:

  • Cloud-based: With Office 365, your files and documents are stored in the cloud, allowing for easy access from anywhere with an internet connection.
  • Collaboration: Office 365 offers robust collaboration tools, including real-time co-authoring, shared calendars, and the ability to collaborate on documents simultaneously.
  • Email and Calendar: Office 365 includes a full-featured email application with advanced calendar functionality, allowing for efficient communication and scheduling.
  • Office Suite: Office 365 provides access to a suite of productivity applications, including Word, Excel, PowerPoint, and OneNote, which are widely used and offer a range of advanced features.
  • Security: Office 365 includes built-in security features, such as encryption, data loss prevention, and advanced threat protection, to help protect sensitive information.


  • Open-source: Thunderbird is an open-source email client, which means that the source code is freely available to the public, allowing for customization and community-driven development.
  • Emails and Filtering: Thunderbird offers a robust email client with powerful filtering capabilities, allowing users to easily manage their inbox and organize their emails.
  • Add-ons and Extensions: Thunderbird supports a wide range of add-ons and extensions, allowing users to customize their email client with additional features and functionality.
  • Privacy: Thunderbird prioritizes user privacy and offers features like automatic email encryption and protection against phishing attacks.
  • Cross-platform: Thunderbird is available on multiple platforms, including Windows, macOS, and Linux, providing flexibility and convenience for users.

Both Office 365 and Thunderbird offer unique features and advantages. The choice between the two ultimately depends on your specific needs and preferences. Office 365 is well-suited for businesses and professionals who require a comprehensive suite of productivity tools, while Thunderbird is a great option for individuals who prioritize customization and open-source software.

Platform Compatibility

When it comes to platform compatibility, Thunderbird and Office 365 have different strengths and limitations.

Thunderbird: Thunderbird is a cross-platform email client, which means it can run on various operating systems such as Windows, macOS, and Linux. This makes Thunderbird a versatile choice for users who switch between different platforms or work in a mixed-platform environment.

Office 365: Office 365, on the other hand, is primarily designed for Windows and macOS operating systems. While there is limited support for using Office 365 on mobile devices and web browsers, the full suite of features and functionalities may be available only on desktop platforms.

Therefore, if platform compatibility is a crucial factor for you, Thunderbird might be the better choice as it offers more flexibility across different operating systems. However, if you primarily work on Windows or macOS and prefer a fully-featured office suite, Office 365 might be a more suitable option.

Email Management

Both Office 365 and Thunderbird offer powerful email management features, allowing users to efficiently handle their email communications.

Office 365

With Office 365, users have access to a comprehensive suite of email management tools. The Outlook application, which is part of the Office 365 package, offers a wide range of features for organizing and managing emails. Users can create folders, apply labels, and use filters to sort their incoming messages. They can also set up rules to automatically categorize and organize their emails based on specific criteria.

In addition, Office 365 provides users with advanced search capabilities, allowing them to quickly find emails based on keywords or sender information. This can be particularly useful for users who receive a high volume of emails and need to locate specific messages quickly.


Thunderbird, on the other hand, is an open-source email client that also offers robust email management capabilities. Thunderbird allows users to create folders and tags to organize their emails. Users can also use filters to automatically sort their incoming messages into specific folders or apply certain actions to them.

Thunderbird also includes a powerful search feature, enabling users to find emails based on various criteria, such as sender, subject, or date. This search functionality can help users locate specific emails in their inbox or other folders.

Both Office 365 and Thunderbird provide users with efficient email management tools, allowing them to stay organized and easily manage their email communications.

Calendar Integration

Calendar integration is an important feature for both Thunderbird and Office 365. Thunderbird, a free and open-source email client, has built-in calendar functionality through its Lightning add-on. This allows users to manage their schedules and appointments directly within Thunderbird, creating events, setting reminders, and syncing with other calendar services like Google Calendar.

On the other hand, Office 365, a popular suite of productivity tools, offers a robust calendar feature within its Outlook application. Office 365’s calendar integration allows users to easily create and manage events, set reminders, and share calendars with colleagues. Users can also access their calendars from any device, making it convenient for those who are constantly on the go.

While both Thunderbird and Office 365 provide calendar integration, there are some key differences. Thunderbird’s calendar functionality is more basic compared to Office 365’s Outlook calendar. Thunderbird lacks some advanced features such as the ability to propose new meeting times or view multiple calendars side by side.

On the other hand, Office 365’s Outlook calendar offers a seamless integration with other Office 365 applications, such as Teams and SharePoint. This allows users to schedule meetings and collaborate with colleagues more efficiently.

Overall, if calendar integration is a top priority for you, Office 365’s Outlook calendar may be the better choice. However, Thunderbird’s Lightning add-on provides a solid calendar solution for those who prefer a free and open-source option.

Contact Management

Both Thunderbird and Office 365 provide contact management capabilities, allowing users to organize and manage their contacts in a convenient way.

Thunderbird offers a built-in address book feature that allows users to store and manage their contacts. Users can create new contacts, add details such as names, email addresses, phone numbers, and additional notes. Thunderbird also supports contact groups, allowing users to organize their contacts into different categories.

On the other hand, Office 365 provides a more comprehensive solution for contact management. Users can create and manage contacts using Outlook, the email client included in Office 365. Outlook offers advanced contact management features, such as the ability to link contacts to calendar events, tasks, and emails. Users can also import and export contacts from other applications or services.

In addition, Office 365 allows users to access their contacts from anywhere, as it is cloud-based. This means that users can access their contacts using any device with an internet connection.

Overall, both Thunderbird and Office 365 offer contact management features, but Office 365 provides a more robust and integrated solution. Depending on the user’s needs and preferences, either option can be a suitable choice.

Security Features

When it comes to security, both Office 365 and Thunderbird offer various features to protect your data and communications. Here are some of the security features provided by each:

Office 365

  • Multi-factor authentication: Office 365 supports multi-factor authentication, adding an additional layer of security to your account by requiring more than just a password for access.
  • Advanced Threat Protection: Office 365 offers advanced threat protection to help safeguard your email from various types of advanced threats such as phishing and malware.
  • Data Loss Prevention: With Office 365, you can set up rules to automatically detect and protect sensitive information, preventing it from being shared or leaked.
  • Encrypted Email: Office 365 uses encryption technologies to ensure that your emails are protected during transit and storage.
  • Secure Collaboration: Office 365 provides secure collaboration features, allowing users to share and collaborate on documents while maintaining control over access and permissions.


  • Open Source: Thunderbird is an open-source email client, meaning its source code is available for anyone to inspect and contribute to. This transparency can help identify vulnerabilities and improve security.
  • Message Encryption: Thunderbird supports various message encryption standards, such as S/MIME and PGP, allowing you to encrypt and digitally sign your emails for enhanced security.
  • Junk Mail Filters: Thunderbird has built-in junk mail filters that help protect against spam and phishing emails.
  • Secure Socket Layer (SSL) Support: Thunderbird supports SSL/TLS encryption for secure email communication with mail servers.
  • Password Manager: Thunderbird includes a built-in password manager that securely stores your email account passwords.

Both Office 365 and Thunderbird offer security features to keep your data and communications protected. The choice between the two ultimately depends on your specific security requirements and preferences.

Collaboration Tools

Both Office 365 and Thunderbird offer a range of collaboration tools to help teams work together more efficiently. These tools include:


Email is an essential collaboration tool for any organization. Both Office 365 and Thunderbird have robust email clients that support features like email filtering, spam protection, and email encryption.


A shared calendar is crucial for coordinating schedules and planning meetings. Office 365 and Thunderbird both provide calendar features that allow users to create and manage events, set reminders, and share calendars with colleagues.

Collaboration Tool Office 365 Thunderbird
File Sharing Yes Yes
Real-time Co-Authoring Yes No
Team Chat Yes No
Video Conferencing Yes No
Task Management Yes No

In addition to email and calendar features, Office 365 offers several advanced collaboration tools that Thunderbird does not have. These include real-time co-authoring, team chat, video conferencing, and task management. These features make it easier for teams to collaborate on documents, communicate in real-time, and manage projects effectively.

However, Thunderbird can still be a suitable collaboration tool for smaller teams or organizations that do not require the advanced features offered by Office 365. Thunderbird’s simplicity and open-source nature make it a popular choice for individuals and small businesses.

Customization Options

Customization is an essential aspect of any software, and Office 365 offers a wide range of customization options to tailor your experience according to your preferences and needs. Whether you are an individual or part of a larger organization, Office 365 allows you to personalize your workspace and maximize your productivity.

Email Customization

With Office 365, you can customize your email settings to suit your communication style. You can change the font, font size, and even the color scheme of your email interface. This allows you to create an email environment that is visually appealing and comfortable for you to work with every day.

In addition, Office 365 provides advanced email filtering options, allowing you to organize your inbox and prioritize your messages effectively. You can set up rules and filters to automatically sort incoming emails into specific folders, making it easier to find and respond to important messages.

User Interface Customization

Office 365 offers a variety of customization options for the user interface. You can choose from different themes and layouts to personalize your Office applications according to your preferences. Whether you prefer a light or dark theme, you can customize the appearance of your Office applications to create an interface that suits your style.

Furthermore, Office 365 allows you to add and remove buttons and commands from the ribbon, giving you control over which features are easily accessible. This customization option allows you to streamline your workflow and access the tools you use frequently without unnecessary clutter.

Email Organization

When it comes to email organization, both Office 365 and Thunderbird offer useful features.

Office 365 provides a range of tools and options to help users stay organized. With its intuitive interface, users can easily sort and categorize emails, create folders, and set up rules to automatically filter messages. The advanced search feature in Office 365 allows users to quickly find specific emails using keywords or filters.

Thunderbird, on the other hand, offers several extensions that can enhance email organization. The Lightning extension integrates a calendar into Thunderbird, allowing users to manage their schedules alongside their emails. Additionally, Thunderbird supports tags and virtual folders, enabling users to categorize emails based on different criteria.

Office 365 Features:

– Intuitive interface for easy sorting and categorizing of emails

– Folder creation and rule setup for automated message filtering

– Advanced search capabilities for quickly finding specific emails

Thunderbird Extensions:

– Lightning: Integration of a calendar for efficient schedule management

– Support for tags and virtual folders for easy email categorization

In conclusion, both Office 365 and Thunderbird offer strong email organization capabilities, but the specific features and extensions they provide may suit different users’ needs. Ultimately, the choice between the two depends on individual preferences and requirements.

Storage Options

When it comes to storage options, both Office 365 and Thunderbird offer different solutions to meet your needs.

Office 365

Office 365 provides users with various storage options to store and access their files. One of the main storage options is OneDrive, which allows users to store files in the cloud and access them from any device with an internet connection. OneDrive offers a generous storage capacity, with plans ranging from 5 GB to 1 TB, depending on the subscription.

In addition to OneDrive, Office 365 also integrates with SharePoint, a collaborative platform that allows users to store and share files within an organization. SharePoint offers even more storage capacity and advanced features, making it an ideal choice for businesses with complex file management needs.


Unlike Office 365, Thunderbird is an email client that does not provide its own storage solution. Instead, Thunderbird relies on the user’s preferred email provider’s storage options. This means that if you use Thunderbird with Gmail, for example, your files will be stored in your Gmail account’s storage capacity.

When it comes to comparing storage options, Thunderbird offers flexibility as it can be used with different email providers, each with their own storage capacity and limitations. However, it’s important to note that the storage capacity may vary depending on the email provider, so it’s worth considering the storage options provided by your chosen email provider before using Thunderbird.

In conclusion, Office 365 provides a comprehensive storage solution with options like OneDrive and SharePoint, while Thunderbird relies on the storage options offered by the user’s email provider. Depending on your needs and preferences, either solution can be a viable choice for storing and accessing your files.

Mobile Access

Both Office 365 and Thunderbird offer mobile access, allowing users to stay productive on the go. With Office 365, you can access your emails, documents, and other files from any device with an internet connection. The Office mobile apps for iOS and Android provide a seamless user experience, with features such as document editing, email management, and calendar integration.

Thunderbird, on the other hand, provides mobile access through its mobile app called Thunderbird for Android. This app allows you to access your emails and manage your inbox while on the move. Although Thunderbird’s mobile app may not have as many features as Office 365’s mobile apps, it still provides a convenient way to stay connected.

Office 365 Mobile Access Features:

  • Email management
  • Document editing
  • Calendar integration
  • Seamless user experience

Thunderbird Mobile Access Features:

  • Email access
  • Email management
  • Convenient mobile app

Cost Comparison

When it comes to cost, Thunderbird has a clear advantage over Office 365. Thunderbird is a free and open-source email client, which means that you don’t have to pay anything to use it. On the other hand, Office 365 is a subscription-based service and comes with a monthly or yearly fee.

While Office 365 offers a wide range of features and services, such as cloud storage, Microsoft Office applications, and collaboration tools, these additional benefits come at a cost. The pricing plans of Office 365 vary depending on the number of users and the specific features you need.

Thunderbird is a cost-effective solution for individuals and small businesses who are looking for a reliable and free email client. It provides all the necessary features for managing emails, contacts, and calendars without any additional charges.

On the other hand, if you require advanced features or need access to Microsoft Office applications, Office 365 might be a more suitable option. However, keep in mind that you will have to pay a subscription fee for these additional services.

In conclusion, Thunderbird offers a no-cost solution for basic email needs, while Office 365 provides a more comprehensive suite of tools and services for a fee.

User Interface

Both Thunderbird and Office 365 offer user-friendly interfaces that make it easy to navigate and access your email. However, there are some key differences in the user interface of these two email clients.

Thunderbird has a clean and simple interface that is similar to many other email clients. It uses a traditional layout with folders on the left-hand side, an email list in the center, and a reading pane on the right-hand side. The interface is customizable, allowing you to change the theme, layout, and toolbar buttons to suit your preferences. Thunderbird also offers a wide range of add-ons and extensions that can further enhance its functionality and customize the interface.

On the other hand, Office 365 has a more modern and visually appealing interface. It utilizes a ribbon-style toolbar at the top, which gives you quick access to various features and functions. The interface is highly interactive and intuitive, making it easy to perform tasks such as composing emails, managing contacts, and setting up calendar events. Office 365 also has a responsive design, which means that it adapts to different screen sizes and devices, providing a consistent user experience across platforms.

In summary, while Thunderbird provides a straightforward and customizable interface, Office 365 offers a more visually appealing and interactive interface. The choice between these two email clients ultimately depends on your personal preferences and the specific features and functionalities that you require for your email management.

Customer Support

When it comes to customer support, Office 365 has a dedicated team available 24/7 to assist its users. You can reach out to them via phone, email, or live chat, and they will promptly address any issues or inquiries you may have.

On the other hand, Thunderbird also offers customer support, but it is community-based. This means that the support mainly comes from fellow Thunderbird users who are part of the community. While this can be helpful, it may not provide the same level of professional and timely assistance as Office 365’s dedicated support team.

If you are someone who requires immediate assistance and wants reliable support, Office 365 is the better choice for you. Their dedicated customer support team is always ready to help, ensuring that any problems you encounter are quickly resolved.

Integration with Other Tools

Both Thunderbird and Office 365 offer excellent integration with other tools, allowing users to seamlessly work with various applications and services.

Thunderbird, being an open-source email client, supports various third-party add-ons and extensions. These add-ons enable users to enhance the functionality of Thunderbird by integrating it with other tools such as calendars, task managers, and cloud storage providers. Additionally, Thunderbird can also integrate with popular email services like Gmail, Yahoo Mail, and Outlook, providing users with a unified interface to manage their emails.

On the other hand, Office 365 provides a comprehensive suite of productivity tools that are tightly integrated with each other. Users can easily access and share files from OneDrive, collaborate on documents in real-time using Office Online, and schedule meetings and appointments using Outlook. Furthermore, Office 365 offers integration with popular communication tools such as Microsoft Teams, allowing users to seamlessly chat, call, and video conference with their colleagues.

In summary, both Thunderbird and Office 365 offer strong integration capabilities with other tools. While Thunderbird’s integration is mostly achieved through add-ons and extensions, Office 365 provides a fully-integrated suite of productivity tools that work together seamlessly.

Migration Process

Migrating from Thunderbird to Office 365 involves a series of steps to ensure a smooth transition of data and settings.

First, backup your Thunderbird data and settings. This can be done by creating a backup of your profile folder, which contains all your emails, contacts, and settings.

Next, set up an Office 365 account. This involves creating a new email account and configuring it with your desired settings.

Once your Office 365 account is set up, you can proceed to migrate your Thunderbird data. This can be done using various methods, such as using the Outlook Migration Assistant tool or manually importing your Thunderbird data into Outlook.

If you choose to use the Outlook Migration Assistant tool, you will need to download and install it on your computer. Once installed, follow the prompts to connect your Thunderbird account and select the data you want to migrate to Office 365.

If you prefer to manually import your Thunderbird data into Outlook, you can do so by exporting your Thunderbird data in a compatible format, such as .pst or .csv, and then importing it into Outlook.

During the migration process, it is important to ensure that all your data is transferred correctly. Take the time to verify that all your emails, contacts, and settings have been successfully migrated to Office 365.

Lastly, once the migration is complete, you can start using Office 365 as your primary email client. Take the time to familiarize yourself with the new interface and features, and don’t forget to update your email settings on any other devices or applications.

Migration Process for Thunderbird to Office 365
1. Backup Thunderbird data and settings
2. Set up an Office 365 account
3. Migrate Thunderbird data using the Outlook Migration Assistant tool or manually import Thunderbird data into Outlook
4. Verify that all data is successfully migrated
5. Start using Office 365 as your primary email client


What is Office 365?

Office 365 is a suite of productivity tools offered by Microsoft that includes popular applications like Word, Excel, PowerPoint, and Outlook. It provides cloud-based storage and collaboration features.

What is Thunderbird?

Thunderbird is a free, open-source email client developed by Mozilla. It is known for its robust security features and customizable interface.

Which one is better for a business user, Office 365 or Thunderbird?

The better choice for a business user depends on the specific needs and preferences. Office 365 offers a comprehensive suite of productivity tools, cloud storage, and collaboration features, making it suitable for businesses of all sizes. Thunderbird, on the other hand, is a lightweight and customizable email client that may be more ideal for individual users or small businesses with simpler needs.

Can I use Office 365 with Thunderbird?

Yes, it is possible to use Office 365 with Thunderbird as an email client. Thunderbird supports the use of Exchange Web Services (EWS), which allows users to connect to their Office 365 email accounts and access their emails, calendars, and contacts.

What are some advantages of using Thunderbird over Office 365?

Some advantages of using Thunderbird over Office 365 include its open-source nature, which allows for customization and community-driven development. Thunderbird is also known for its strong privacy and security features, and it can be a cost-effective solution for individuals or small businesses who do not require the full suite of Office 365 tools.

What are the main differences between Office 365 and Thunderbird?

The main differences between Office 365 and Thunderbird are their functionality and the platforms they are available on. Office 365 is a comprehensive suite of productivity tools that includes email, calendar, word processing, spreadsheets, and more. It is available on multiple platforms, including Windows, Mac, and mobile devices. Thunderbird, on the other hand, is primarily an email client that is available for Windows, Mac, and Linux.

Which one is better for business use, Office 365 or Thunderbird?

For business use, Office 365 is generally considered to be a better option than Thunderbird. Office 365 provides a full suite of productivity tools that are essential for business operations, such as email, calendar, document collaboration, and more. It also offers enterprise-level security and compliance features. Thunderbird, while it can be used for business email, lacks the comprehensive feature set and integration capabilities of Office 365.

Is Thunderbird a free software?

Yes, Thunderbird is free and open-source software. It can be downloaded and used for free on multiple platforms, including Windows, Mac, and Linux. Thunderbird is maintained and developed by the Mozilla Foundation, which is known for its commitment to open-source software and community-driven development.