The Best Email Apps for Windows

By Spike Team, October 12, 2021
Windows 10 Email client

If you’re looking for a Windows  email client, there is no shortage of excellent options, from conversational email apps to those that merge your calendar into your inbox. Before considering what email client to use with Windows, it’s essential to consider what criteria you define as necessary to match your needs to the best app for your use case.


When selecting an email client, it’s imperative to use solutions that rely on open email protocols so you’ll be able to switch to another application in the future easily.



Key Terms to Know About E-mail

Before we talk about apps and email clients for Windows, let’s talk about some key terms to know about email. 

What is IMAP?

IMAP technology allows you to access your email from any device while keeping your other devices in sync. When you read an email message using IMAP, you aren’t downloading or storing it on your computer; instead, you’re reading it from the email server. As a result, you can check your email from different devices using different apps from anywhere in the world: your phone, a laptop, a public library computer, etc. Reading messages on one device will mark them as read on all other devices.

What is POP3?

POP3 is one of the oldest email protocols still being used. A POP3 server receives emails, stores them locally  and filters them into the appropriate folders. When a user connects to the mail server using their Windows email client to retrieve their mail, the messages are downloaded from the mail server to the user’s hard drive. 

What is SMTP?

SMTP (Simple Mail Transfer Protocol) was created in 1981 and is being used by mail servers to send, receive, and/or relay outgoing mail between email senders and receivers.

What is an Email Client?

An email client is a local application that allows you to view the email on your email server and send new email messages. An alternative to an email client is a web interface that will enable you to view your email messages.


Finding the right email client is like finding the perfect size on a great pair of pants. Sometimes you just need to try a few on to see which one fits your workflows the best. 



How did we Research the Best Email App for Windows in 2021?

To find the best email app for Windows, we measured them against seven key parameters. These guidelines gives us a good foundation on which to judge them individually and an easy way to compare them to one another so you can find the email client that’s right for you. 


The parameters are:

  1. Design

    If the meteoric rise of Apple has proven anything, it’s that design matters. While two competing platforms may offer similar features if one is clear at a glance and the other clunky with a kind of 90s vibe, it’s obvious which one you’re going to choose. 

  2. Support for multiple accounts

    There are more than four billion email users worldwide, and each has an average of two accounts. People looking for an email client may have many more than this, and the last thing they want is to have to go to multiple different places to read messages. Support for more than one email account (whether business or personal) is a key parameter to look for. 

  3. Ease of use

    You may be a tech wizard, but not everyone is. And anyway, even wizards like a bit of convenience sometimes! Therefore, we looked into how easy to use each of the apps were. This includes setting them up, accessing the tools, and connecting with people inside and outside of your company. 

  4. Number of features

    The number of useful features that each application offers. This includes, but isn’t limited to:


    • An integrated calendar
    • Real-time chat
    • Video and voice integration
    • Advanced mail sorting 
    • Integrated task management tools 
  5. Operating system

    These days, it’s extremely rare that a person will only use one device to check their emails. At a minimum, they will likely be using a laptop or desktop and a smartphone. Add into the mix that they may want to check it on someone else’s hardware or work across multiple computers (office and home, for example), and that’s a lot of operating systems to cover. Therefore, in addition to Windows, we looked into whether an app was available for macOS, iOS, Android, and as a web application

  6. Security

    Security is an increasingly important topic for email users, so as part of our research into the best email apps for Windows, we considered two aspects of security:

    • Does the company providing the email client protect your data?
    • Can your email be secured through encryption? 
  7. Pricing

    The final point that we considered — and by no means the least important — was the price of each email client. This is especially important for those looking for email clients for their entire team since expensive subscriptions can quickly stack up. 


With these seven criteria in mind, let’s take a closer look at each of the Windows email apps that we compared. 



Spike Email for Windows 10

With so many different use cases for Windows email clients, Spike strikes a healthy balance of allowing business users and home users to manage their email in a modern way. Spike’s Conversational Email brings together the best of email and a messenger app in a simple, fast, and secure email chat. Some of the critical features that Spike unlocks are Snooze and Schedule Send. Snooze allows you to hide emails until you’re more able to focus on them, and Schedule Send will enable you to pre schedule emails for a different time to be delivered automatically regardless if the Spike app is open or not.


Spike’s digital workspace includes built-in document management, collaborative notes, shared tasks, and workplace chat. Priority Inbox is a crucial feature for users who get hundreds of emails per day as it automatically prioritizes more important emails over less important ones.

  • Design

    Spike offers a sleek and modern interface with a user-first design. Tools, information, and more can be found easily through a clear and well-thought-out layout. Spike also offers customization of group icons as well as the option for light, dark, and system themes. 

  • Support for multiple accounts

    Spike supports email accounts from Gmail, G Suite, Outlook, Yahoo, Hotmail, iCloud, Microsoft 365, Outlook, IONOS mail, GoDaddy email, Exchange, AOL, and standard IMAP mail accounts.


    This means all your emails in a single, unified location. 

  • Ease of use

    You are able to sign up to Spike for free with an email address from the web. To make things even easier for Windows  users, Spike is available on the Microsoft Store. Once you’re using Spike, it’s easy to communicate with people inside and outside of your organization since it’s a productivity platform built around email. 

  • Number of features

    Spike offers all the tools you’d expect in an email client, as well as so many more. It packs everything you need from a full productivity suite into a single inbox, so you never need to switch between a dozen apps again. Some of the key features you can expect are:


    • Online Collaborative Notes
    • Tasks and To-Do Lists
    • Groups
    • Integrated Calendar 
    • Advanced Search
    • File Management
    • Advanced Email Management 
  • Operating system

    Spike is available for Windows, of course, as well as on Android, iOS, and macOS. There is also a web-based application to access all your emails from any device. 

  • Security

    It is ad-free and doesn’t rent, sell, distribute or monetize your data ever. You don’t have to just take their word for it. Spike passed a security audit by an independent security evaluator (ISE). 


    As far as outside (potentially malicious) actors getting at your emails and data? Well, with Spike, message data is encrypted using AES-256 encryption. 

  • Pricing

    Spike allows you to have unlimited personal addresses for free! Beyond that, solo business accounts are $12 per account/month billed annually. If you’re looking to get a modern email app for your team, group Business accounts are just $8 per account/month billed annually. 



Thunderbird Email for Windows 10

Mozilla Thunderbird is one of the oldest email apps on the market that is still in active development. In late 2004, version 1.0 of Thunderbird was released and received more than 500,000 downloads in its first three days of release and 1,000,000 in ten days. It was a popular alternative to Outlook and Outlook Express for Windows XP users. It remained popular, but its growth languished behind Firefox. As Google’s Gmail gained in popularity, the need for a desktop-based email client decreased in popularity.


In recent years, the popularity of desktop-based email systems increased as users looked for more robust solutions in a multiple device world. Native applications surged in popularity on mobile devices, so users began to look for native solutions on the desktop to sync up their experiences. Thunderbird resumed full-time development in 2017.


Thunderbird is now a popular Windows email client. Thunderbird claims it’s more straightforward and safer for users with features like a robust spam filter and quick search abilities. With a built-in calendar, Thunderbird lets you organize your schedule and important events in a calendar that’s fully integrated with your email. You can view multiple calendars, create a daily to-do list, invite people to events, and subscribe to public calendars like a holiday calendar.


Thunderbird is an open-source project, which means anyone can contribute ideas, designs, code, and time helping fellow users. 

  • Design

    While Thunderbird has certainly been modernized since its original iterations, the user interface is still slightly clunky. That said, it does ship with light and dark themes with the option of using others through add-ons. 

  • Support for multiple accounts

    Mozilla Thunderbird offers support for multiple accounts within their email client. 

  • Ease of use

    Once requiring manual setup for IMAP, SMTP, and SSL/TLS settings, Thunderbird now offers a Mail Account Setup Wizard, making it far easier to set up. It also offers other usability functions such as attachment reminders and a quick-add address book. 

  • Number of features

    Thunderbird is an email client first and foremost and therefore offers key features such as search tools, message archiving, and folders for organization. One feature that is highlighted is their “tabbed emails,” which, like a browser, opens different emails in different tabs and might be useful for some people’s workflows. More features can be acquired through add-ons, but this requires extra work. Thunderbird now also ships with a calendar. 

  • Operating system

    Thunderbird is available on Windows, Mac, and Linux. If you want to get it on other platforms, you have to build it from source code. This means no taking your mail mobile. 

  • Security

    The open-source nature of Thunderbird allows you to view the source code, giving a layer of protection to those in the know. Additionally, Thunderbird blocks remote images, offers Phishing Protection, including warnings about deceptive links, and has a robust junk mail filter. 

  • Pricing

    Since it’s open-source, Thunderbird is free to download. 


Outlook for Microsoft 365

Microsoft 365


Included with a Microsoft 365 subscription, Outlook is one of the oldest applications available on any platform. Even though it shares the same name as the older version, the current Outlook is a lot different than the one businesses used in the early 2000s.


Outlook is included for free with a Microsoft 365 subscription, and it works with Microsoft Outlook/Hotmail email, Gmail, Yahoo, iCloud, and more. It consists of several features aimed at business users with a detailed calendar, detailed task manager, and a contacts manager.


One of the most popular Outlook features for Windows is the ‘plan your day’ feature with calendars. You can see multiple calendars at the same time side-by-side or combined into a stacked overlay view to help you see availability across all of your calendars.

  • Design

    The design could be positive for Windows users since Outlook follows many of the same lines as other Microsoft products. What’s more, it has come on a long way since the early days, especially the mobile app. 

  • Support for multiple accounts

    Outlook supports multiple email accounts within a single client. This includes Microsoft Outlook/Hotmail email, Gmail, Yahoo, iCloud, and more. 

  • Ease of use

    While the initial setup of Outlook is relatively simple, the Microsoft 365 ecosystem as a whole can be extremely confusing. This is especially true of business accounts, which can require diving into website DNS records. 

  • Number of features

    The core features of Outlook are email, calendar, contacts, and files. Unfortunately, to access additional features when using Outlook, you need to switch to another program in the Microsoft 365 suite. While this doesn’t add cost, it does waste time and energy. For example, any time you want to make a video or voice call, you have to switch to Microsoft Teams

  • Operating system

    Outlook for Microsoft 365 is available for Windows, macOS, iOS, and Android. They also offer a web interface. 

  • Security

    Office 365 Family and Personal offers virus protection, anti-phishing, anti-spam, link, and attachment scanning. Outlook also supports S/MIME encryption and Microsoft 365 Message Encryption, which requires both sender and recipient to have it enabled and purchase an Enterprise E3 license. 

  • Pricing

    Microsoft 365 Personal starts at $69.99 / year for a single person. For businesses, it starts at $5.00 per user/month for Microsoft 365 Business Basic when paid annually. Office 365 E3, which is required for the Microsoft 365 Message Encryption, starts at $20.00 user/month with an annual commitment. 



MailBird email for Windows 10


Mailbird is a lightweight email client for Windows with an open design. It was originally inspired by the Sparrow email client for OS X and launched in 2013. Since then, it has gone through a couple of major updates in 2015 and again in 2020, which both added a number of features.

  • Design

    You can choose themes, including a full dark theme option, and use horizontal and vertical orientations for tabs and emails. It focuses on providing an uncluttered interface for intuitive use. 

  • Support for multiple accounts

    You can add multiple accounts to Mailbird. If your mail provider’s IMAP or POP3 settings are known, there is a relatively simple setup wizard. If not, all server information, etc., must be entered. 

  • Ease of use

    Mailbird offers free email support to users as well as multi-language support and keyboard shortcuts for various activities. The email client also has some of its features, such as contact organization, on a drag-and-drop system which some users may find more intuitive than other email apps. 

  • Number of features

    Mailbird offers a diverse range of features, including speed reading, integrations with services like LinkedIn, Facebook, and WhatsApp. Mailbird also includes a snooze feature and undo send option. In 2020, they added a calendar, advanced search, and the ability to move emails between accounts. Some of these features, however, are only available for business accounts. 

  • Operating system

    As of now, Mailbird is a Windows-only application. Therefore, if you use multiple devices, you might struggle. That said, Mailbird for Mac is in the works. 

  • Security

    The information sent and received by Mailbird is done over an HTTPS connection and all emails, attachments, passwords, etc., are stored locally. 

  • Pricing

    Mailbird Personal is available for $19.50 per year billed annually or $39.50 as a one-off payment. For business accounts, this jumps $29.50 per year, per instance. 


Mail and Calendar for Windows 10

Microsoft Mail for Windows 10


The Mail and Calendar app for Windows 10 will satisfy the needs of a lot of people simply because it’s free and built right into Windows 10. It supports Microsoft 365, Exchange,, Gmail, Yahoo!, and other popular email accounts.


Overall, it’s a basic email program, though. If your only needs are sending and receiving email, but otherwise, it won’t satisfy any of your needs. You can’t set up message filters, for example, email groups or templates. It also lacks such features as Snooze and Schedule Send. The only people who use it are those who don’t know how to install other applications or cannot due to company policy.

  • Design

    The design of this email client is essentially Windows 10 as a mail client. As in, it looks just like your Windows 10 desktop. For some, this could prove a positive, but for most, it will only cause trouble. 

  • Support for multiple accounts

    Mail and Calendar for Windows 10 supports multiple email accounts, including Office 365, Exchange,, Gmail, and Yahoo! 

  • Ease of use

    The lack of features does make Mail and Calendar for Windows 10 relatively easy to use. Combined with the fact that it comes preloaded with Windows 10, this would be the simplest email client by far for the completely non-tech savvy. 

  • Number of features

    This is an app that very much does what it says. It offers email and a calendar for Windows 10. If you’re looking for more advanced features, look elsewhere. 

  • Operating system

    Unsurprisingly, it is available only on Windows 10. 

  • Security

    If you’re happy with how Windows 10 handles your data, then you should be equally as satisfied with how Mail and Calendar for Windows 10 does it. 

  • Pricing

    Free for Windows 10 users. 

eM Client for Windows



eM Client is a newcomer to the Windows email client area. It includes popular features like message encryption, snooze, message translations, watch for replies, and more. It works on macOS and Windows, but it lacks a mobile app. Many people looking for a desktop app will want a mobile version that matches its feature set so they can have the same experience on all of their devices.


eM client focuses on making it easy to manage a universal inbox with all of your personal and work email accounts. It also focuses on organizing your contacts and creating a great calendar experience.

  • Design

    A minimalist design with a lot of customization makes it an upgrade over the built-in Email app on Windows. The design does a nice job of breaking out Tags into a separate feature.

  • Support for multiple accounts

    eM client supports Google Workspace, Gmail, iCloud, Yahoo, Microsoft Exchange, Kerio, and even mail servers running on macOS Server.

  • Ease of use

    eM client performs a lot like an upgraded version of Microsoft Outlook. It provides a traditional email experience with a few upgraded bells and whistles.

  • Number of features

    Like we mentioned in the beginning, eM client offers a lot of upgraded features over a web app or the built-in Windows email client. One of the main upgraded features it offers is a sidebar that lets you quickly access your community history, attachment history, calendar, agenda, and more. It also contains snooze, templates, watched replies, and more.

  • Operating system

    The app is available for Mac and Windows 10/11

  • Security

    eM client supports PGP encryption with the eM KeyBook. eM Keybook is a Public Key directory managed by eM Client. It’s an online service where you can upload and manage your public keys so anyone can easily send you encrypted messages and you can easily get public keys of the people you’re sending messages to.

  • Pricing

    eM Client is free for personal use, and business customers can access additional features for a 1-time payment of $49.98. The free version only allows you to manage 2 email accounts at a time.


Kiwi for Gmail




If you love Gmail or Google Workspace, but you need an upgraded desktop experience, Kiwi for Gmail might be an app worth checking out. It’s designed and built to let you use Gmail and Google’s office suite outside your web browser as a standalone application.


  • Design

    Kiwi looks a lot like the traditional Google email web experience, but with some additional features to help make it work better.

  • Support for multiple accounts

    Kiwi for Gmail works with multiple Gmail and Google Workspace accounts, but it cannot work with iCloud, Yahoo, or any other email platform besides Google.

  • Ease of use

    If you love using Gmail on the web, but want a more desktop-class experience, Kiwi for Gmail aims to provide that.

  • Number of features

    Kiwi for Gmail is a great app if you manage multiple Gmail/Google Workspace accounts. It lets you easily access all of your documents, emails, and more.

  • Operating system

    The app is available for Mac and Windows 10/11

  • Security

    Kiwi for Gmail access your Google accounts through Google OAuth so it’s secure. You can easily revoke access in the future from your Google account settings page.

  • Pricing

    Accessing 1 account is free, but to use Kiwi for Gmail with up to 6 accounts requires a $34.99 annual subscription. The premium upgrade includes additional features like the Boomerang subscription and more. For $58.99/year, you can add up to 14 Gmail/Google Workspace accounts.


How to Install a New Windows Email Client

Most email apps come in either a .exe or .msi file format. As long as you have sufficient privileges on your Windows computer, all you need to do is download the file from the app developer’s website and double-click the file that is installed.


The Microsoft Windows App Store is another popular place to find a new email application with a more straightforward installation process. You’ll just need to search for the email app you want (Try ‘Spike’) on the Microsoft Store and view the available options with a 1-click install button.


For more information on making the most of email, check out the Spike blog today or Tweet us @SpikeNowHQ.



Email Apps for Windows FAQs

The best email app for Windows in 2021 depends heavily on your use case. If you want a bare-bones email client, there are certainly some good options out there. But for a more robust option, consider looking at Spike, which has numerous productivity features and cross-platform functionality for when you’re on the move. 

If you’re looking for free and easy, then Mail and Calendar for Windows comes included. However, if you’re reading this, then the baked-in client probably doesn’t quite cut it for you. Spike allows you to have unlimited personal addresses for free! 

First, consider whether you need a new email provider or just a new email client. You can stick with your Gmail account but access it through a more robust platform. Spike, for example, allows you to connect a Gmail account but adds features such as Online Notes, Tasks and To-Do Lists, and more. 


Spike Team The Spike team posts about productivity, time management, and the future of email, messaging and collaboration.