Thunderbird
A free email, calendar and contacts app that works with any mail provider.
Instead of Gmail's web app and Outlook
Screenshot from www.thunderbird.net, taken 2026-10-23, shown to help you recognise the tool. It belongs to its maker. Ask us to remove it.
Plenty of people have had the same email address for fifteen years and dread the day they might have to change it. Thunderbird is part of the Mozilla family, says it is free forever and is funded by user donations. It combines mail, calendar and contacts, with a unified inbox, tags, filters and extensions, on Windows, Mac, Linux and Android. It works with the mail accounts you already have, so you can leave Gmail's interface without leaving your address.
It keeps mail on your own computer and speaks standard protocols, so you can switch providers without losing your archive, and it does well on Lock-in and Longevity. Thunderbird scores a 5 on lock-in and longevity, a 4 on self-direction, power and delivery and a 3 on footprint.
It is a mail app and not a mail service, so it does not replace your provider, and its look is older than the web apps. We could not confirm its licence from its site.
- Mail, calendar and contacts in one app from the Mozilla family
- Works with the mail accounts you already have
- Keeps mail on your own computer and speaks standard protocols
What stands out
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Side by side. Thunderbird vs Gmail
For comparison, we also reviewed Gmail (16/30) as a benchmark.
