Microsoft Outlook vs Thunderbird
We give Microsoft Outlook a 3.8 GPA and Thunderbird a 3.6, out of 4.0. Microsoft Outlook grades higher on platforms. They get the same grade on value for money, the free plan, features and ease of use.
Price, platforms and features side by side. The table says where each price was read and when.
Microsoft Outlook
Microsoft's email and calendar app for desktop, mobile and web
Thunderbird
Free, open-source email app for Windows, macOS, Linux and Android
How we grade them
| 3.8GPAMicrosoft OutlookExcellent | 3.6GPAThunderbirdExcellent | |
|---|---|---|
| Value for money | AMicrosoft 365 Basic is $1.99 a month, or $19.99 a year. That takes the ads out and lifts your mailbox from 15 GB to 100 GB. Proton's cheapest paid plan is $3.99 and stops at 15 GB. | AIt's free, so there's no price to weigh. Every feature of the desktop and Android apps costs $0, with no ads and no paid tier. Development is funded by voluntary donations. Thundermail, the team's own hosting service, is a separate paid subscription and still in beta. |
| Free plan and trial | AA real free plan, not a trial: 15 GB for mail, apps for your phone and your computer, and your Gmail, Yahoo and iCloud accounts in the same place. You pay in ads, and they sit right in the inbox. | AThe whole app is free on desktop and Android, with nothing held back for a paid plan, because there isn't one. The trade-off is support. It's community-based, and Thunderbird states that donations do not buy individual technical support. |
| Features | AFocused Inbox, Sweep, snooze, a calendar, contacts and to-do lists in one window. It'll even track parcels and flights. Copilot writes and summarises too, but that's on the $9.99 plan. | ASeveral accounts, read separately or in a unified inbox, with a calendar, contacts and tasks in the desktop app, so scheduling doesn't need a second program. Add-ons extend it further. On Android, advanced users can add OpenPGP by pairing it with the free OpenKeychain app. That's the whole job of a mail app. |
| Ease of use | B4.8 from about 9.3 million App Store ratings, so the phone app is doing something right. Computers are messier. Windows has a new Outlook and a classic one, and Microsoft keeps a help page called "What version of Outlook do I have?" | BNo rating on record, so a B is our ceiling. It's an app you install and add your accounts to. One nice touch: desktop users can move their account settings to the Android app by scanning a QR code. |
| Platforms and integrations | AWeb, Windows, Mac, iPhone and Android, where Gmail lists no desktop app at all. It plugs into Teams, OneDrive, Word and Excel as well. No Linux app, though. | BWindows, macOS and Linux on the desktop, and Android on the phone. No iPhone or iPad app is listed, which is a real gap. It connects to accounts hosted elsewhere, and add-ons extend what the desktop app can do. |
| Best for | all your inboxes and a calendar in one app | free, open-source email on any desktop |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: Microsoft Outlook and Thunderbird. How we grade
Where they differ
- Microsoft Outlook starts at $1.99 per month, or $19.99 per year (Microsoft 365 Basic). Thunderbird is free.
- Only Microsoft Outlook lists a web app.
- Only Microsoft Outlook lists an iOS app.
- Only Thunderbird lists a Linux app.
- Thunderbird is open source, according to its own site.
- Microsoft Outlook also covers inbox filtering.
At a glance
| Microsoft Outlook | Thunderbird | |
|---|---|---|
| Pricing | Free plan | Free |
| Starts at | $1.99 per month, or $19.99 per year (Microsoft 365 Basic) | Free |
| Free plan | Free Outlook for 1 person: email and calendar on the web, desktop and mobile apps, 15 GB of mailbox storage, 5 GB of cloud storage and core spam filtering. The free inbox shows ads. | The whole app is free on desktop and Android, with no ads and no paid tier. Development is funded by voluntary donations. |
| Free trial | One-month free trial of the Microsoft 365 business plans, credit card required; Personal and Family also offer a free trial | None listed |
| Web | ||
| macOS | ||
| Windows | ||
| Linux | ||
| iOS | ||
| Android | ||
| Made by | Microsoft | MZLA Technologies Corporation |
| Price read from | microsoft.com | thunderbird.net |
| Checked | Oct 9, 2026 | Oct 5, 2026 |
Who each one suits
Microsoft Outlook
- People who want mail, calendar and contacts from several accounts in one app
- Organizations already paying for Microsoft 365 and Exchange email
- Windows users: Microsoft says Outlook is included free with Windows
Thunderbird
- People who want a free desktop email app without ads
- Linux users, and anyone moving between Windows, macOS and Linux
- Those who prefer open-source software for mail and calendar
Worth knowing
Microsoft Outlook
- Free accounts show ads in the inbox; a Microsoft 365 Basic, Personal or Family subscription removes them.
- Business Basic has only web and mobile Outlook. Apps for business ($10.00) adds desktop Outlook without business email; Business Standard with Copilot ($23.50) has both.
- On home plans, Copilot in Outlook currently works only with outlook.com, hotmail.com, live.com and msn.com addresses, and only for the subscription owner.
- Microsoft lists Outlook for Windows, macOS, iOS, Android and the web. No Linux app is listed.
Thunderbird
- Thunderbird Mobile is listed for Android only, through Google Play and F-Droid. No iPhone or iPad app is listed.
- It is a mail client, not a mailbox: it connects to accounts hosted elsewhere. The team's own hosting service, Thundermail, is in beta behind a waitlist.
- Thundermail is a separate paid subscription. Its Early Bird Plan is shown at $6 per month, paid annually, with full launch expected in 2026.
- Support is community-based. Thunderbird states that donations do not buy individual technical support.
Key features
Microsoft Outlook
- Several accounts in one app
- The desktop and mobile apps take Outlook.com, Gmail, Yahoo, iCloud and other mail services alongside work or school accounts, and switch between them without leaving the app.
- Focused Inbox, Sweep and snooze
- Focused Inbox and Sweep clear clutter out of the main view. Messages can be snoozed until later or flagged as important.
- Calendar, contacts and to-do lists
- Email, calendars, contacts and to-do lists sit in one view. Outlook can schedule events, set reminders, and track packages and flights on supported platforms.
- Copilot in Outlook
- Drafts a message from a prompt, adjusts tone, length and clarity, and summarizes long threads. Included with Microsoft 365 Personal and Family, with usage limits.
- Mailbox protection
- Outlook scans attachments and links for threats on Microsoft email addresses. Paid plans add mailbox encryption, checks on suspicious links and removal of dangerous attachments.
- Office files from the inbox
- Open, edit or send Word, Excel and PowerPoint documents from the inbox, and attach OneDrive files as links.
Thunderbird
- Unified inbox for several accounts
- Keep every email account in one app and read them separately or together in a unified inbox, on desktop and on Android.
- Calendar, contacts and tasks
- The desktop app manages appointments, contacts and tasks alongside email, so scheduling does not need a separate program.
- No ads or data mining
- Thunderbird says it does not sell ads in the inbox, collect personal data or train AI on private conversations. It is funded by user donations.
- Open source and extensible
- The code is published under the MPL 2.0 license for anyone to inspect, modify and share, and add-ons extend what the desktop app can do.
- OpenPGP encryption on Android
- Advanced users can send and receive encrypted mail with the OpenPGP standard by pairing Thunderbird Mobile with the free OpenKeychain app.
- Desktop-to-mobile setup
- Desktop users can move their account settings to the Android app by scanning a QR code shown in the desktop app.
Plans
Microsoft Outlook
Outlook$0
For 1 person: email and calendar on web, desktop and mobile, 15 GB of mailbox storage, 5 GB of cloud storage and core spam filtering, with ads.
Microsoft 365 Basic$1.99
per month, or $19.99 per year
For 1 person: ad-free Outlook, 100 GB of mailbox storage, 100 GB of cloud storage and advanced Outlook security features.
Business Basic$7.00
per user / month, paid yearly ($5.40 without Teams)
Custom business email on Exchange for up to 300 users, with the web and mobile versions of Outlook only and 1 TB of cloud storage per user.
Microsoft 365 Personal$9.99
per month, or $99.99 per year
For 1 person on up to 5 devices at once: the Outlook desktop app with Copilot, 1 TB of cloud storage and Microsoft Defender.
Microsoft 365 Family$12.99
per month, or $129.99 per year
The Personal benefits for 1 to 6 people, who share 2 TB of cloud storage between them. AI features are for the subscription owner only.
Business Standard with Copilot$23.50
per user / month, paid yearly ($20.30 without Teams)
Adds desktop versions of Outlook and the other Office apps, plus Copilot grounded in work data. Business Premium with Copilot is $32.00.
Thunderbird
Free$0
Every feature of Thunderbird Desktop for Windows, macOS and Linux and of Thunderbird Mobile for Android.
Ways to pay less
Microsoft Outlook
- Annual discount
About 16% lower with yearly billing
Paying yearly costs $19.99 for Microsoft 365 Basic, $99.99 for Personal and $129.99 for Family, against $1.99, $9.99 and $12.99 a month.
- Education
Students save 50% on Microsoft 365 Personal
College and university students who verify their status get 50% off Microsoft 365 Personal, which includes the Outlook desktop app with Copilot. Eligibility is re-verified each year.
- Nonprofit
Business Basic free for eligible nonprofits
Microsoft lists Business Basic as a grant, free for up to 300 users. Nonprofit staff pricing is $3.50 per user / month for Business Standard and $5.50 for Business Premium, paid yearly.
Thunderbird
No public discounts listed.
