eM Client vs Thunderbird

Price, platforms and features side by side. The table says where each price was read and when.

eM Client

Desktop email client for Windows and Mac with calendar and chat

Free plan · from $39.95/yr

Thunderbird

Free, open-source email app for Windows, macOS, Linux and Android

Free

Where they differ

eM Client starts at $39.95 per year (Personal subscription, up to 3 devices). Thunderbird is free.
Only eM Client lists an iOS app.
Only Thunderbird lists a Linux app.
eM Client can be bought with a one-time purchase.
Thunderbird is open source, according to its own site.
eM Client also covers notes.

In commonFree planWindowsmacOSAndroidTasksCalendarEmail client

	eM Client	Thunderbird
Pricing	Free plan	Free
Starts at	$39.95 per year (Personal subscription, up to 3 devices)	Free
Free plan	Free license for personal, non-commercial use: 2 email accounts on one device, with email, calendar, contacts and tasks. The Android and iOS apps are free and need no license.	The whole app is free on desktop and Android, with no ads and no paid tier. Development is funded by voluntary donations.
Free trial	30-day free trial of all features, plus a 30-day money-back guarantee	None listed
macOS
Windows
Linux
iOS
Android
Made by	eM Client s.r.o.	MZLA Technologies Corporation
Price read from	web.archive.org (not the vendor's own page)	thunderbird.net
Checked	Oct 5, 2026	Oct 5, 2026

eM Client

Thunderbird

eM Client

The Free license is for personal, non-commercial use only, on one device with 2 email accounts.
Thread view, notes, snooze, Send Later, undo send and message translation need a paid Personal or Business license.
A one-time license covers the current major version only. Later major versions need a paid upgrade or the Lifetime Upgrades option.
No Linux or web version is listed. The pricing page shows different prices by country; the figures here are the US ones.

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.

eM Client

Works with most email services: Connects to Google Workspace, Office 365, Outlook, Exchange and other services, and imports data from Microsoft Outlook, Thunderbird and other clients.
Calendar, tasks, contacts and notes: Calendars, tasks and contacts are part of every license, with a sidebar agenda of upcoming events, tasks and birthdays. Notes need a paid license.
PGP and S/MIME encryption: Messages can be encrypted and digitally signed with S/MIME or PGP. The pricing table lists this on the Free license too.
Snooze, Send Later and Watch for Reply: Paid licenses add snooze, scheduled sending, undo send, a watch for replies to sent messages, mass mail and a view of all attachments.
AI and translation: AI generates messages and replies or adjusts the tone of a draft through the AI Add-on, which subscriptions include. Paid licenses also translate incoming messages.
Chat and meeting integrations: Chat and online meeting integration are built in, and paid licenses add Microsoft Teams, Slack and Rocket.Chat integration.

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.

eM Client

Free$0
Personal, non-commercial use on one device with 2 email accounts and forum support. No snooze, Send Later, notes, thread view or translation.
Personal (subscription)$39.95
per year, for 1 user on up to 3 devices
Individual use with unlimited email accounts, every feature, VIP support, new major versions and the AI Add-on included.
Business (subscription)$49.95
per device / year
Company or institutional use, priced per device and lower in volume. Adds the License Manager, with VIP support and the AI Add-on included.
Personal (one-time)$59.95
one-time payment, for 1 user on up to 3 devices
Never expires for the current major version and includes 1 year of VIP support. Later major versions and the AI Add-on cost extra.
Business (one-time)$79.95
per device, one-time payment
Per-device company license that never expires for the current major version. Lifetime Upgrades are an optional extra.

Thunderbird

Free$0
Every feature of Thunderbird Desktop for Windows, macOS and Linux and of Thunderbird Mobile for Android.

eM Client

Lifetime license
One-time payment instead of a subscription
Personal at $59.95 or Business at $79.95 per device buys a license that never expires for the current major version. Optional Lifetime Upgrades extend it to all future versions.
Nonprofit
30% discount for NGOs
The pricing page states that NGOs are eligible for a 30% discount, arranged by contacting eM Client.
Education
30% discount for schools and universities
Schools and universities are eligible for the same 30% discount, arranged by contacting eM Client.

Thunderbird

No public discounts listed.