BlueMail vs K-9 Mail (2026): which should you pick?
As of Nov 13, 2026, BlueMail grades higher than K-9 Mail: 3.2 against 2.8 out of 4.0.
Checked Oct 5, 2026 and Nov 13, 2026 · graded Oct 10, 2026 and Nov 13, 2026 by ToolGPA
BlueMail grades higher on ease of use and platforms. K-9 Mail grades higher on value for money. They get the same grade on the free plan and features.
Price, platforms and features side by side. The table says where each price was read and when.
BlueMail
Cross-platform email client with a unified inbox and built-in AI
Which one is for you
Pick BlueMail if
- Fits if you want the same email app on your phone, your Mac and a Linux machine
- Works for people with several accounts, since the free plan takes unlimited ones
Look elsewhere if
- Skip it if you want email in a browser tab, as there's no web version
- Not for you if you need S/MIME, SSO or MDM support, which are listed on the Enterprise plan only
- Tight if you were hoping for free AI, because GemAI starts on Plus at $35.99 a year
- Watch out: the website prices Plus at $4.99 a month or $35.99 a year, but the App Store shows $6.99 and $49.99
- Watch out: the Plus trial is 7 days, and the FAQ ties it to yearly subscriptions
Pick K-9 Mail if
- Fits if you read several mailboxes on one Android phone
- Works for people who want GPG and open-source code
Look elsewhere if
- Not for you if you use iPhone or a computer, as it is Android only
- Watch out: the site's banner says Thunderbird for Android is the future of K-9 Mail
- Skip it if you need a new address, since it is a client for existing mailboxes
- Tight if you want setup done for you, as you add your own account details
How we grade them
| 3.2GPABlueMailVery good | 2.8GPAK-9 MailGood | |
|---|---|---|
| Value for money | BPlus is $35.99 a year, which BlueMail shows as $3 a month, inside the lowest-priced quarter for this category, where the middle is $8. That buys unlimited GemAI, desktop backup and priority support. Pay monthly and it's $4.99, and the US App Store shows different in-app figures, $6.99 and $49.99. | AFree to download under the Apache 2.0 licence, with no paid plans, and a donate link. |
| Free plan and trial | AThe Personal plan is free for good with no cap a normal person would reach: unlimited email accounts, the unified inbox, Clusters, MagicSync and PGP encryption, on every platform. GemAI and desktop email backup are held back for Plus. | AThe full app is free from Google Play, F-Droid, GitHub or Amazon. |
| Features | BIt covers the mail-client job: one inbox for every account, Clusters that group newsletters and receipts, a screener that holds mail from new senders for review, a calendar inside the app that proposes times from a thread, and PGP with your own keys. S/MIME is Enterprise only. | BPush IMAP, GPG and PGP/MIME, a unified inbox, identities and message tools. The listing shows no gap in the core job of a mail client, though it provides no address of its own. |
| Ease of use | BNo app rating on record, and nothing to set up beyond signing in: it takes Gmail, Outlook, Yahoo, iCloud, Exchange and any IMAP or POP3 account, as many as you like, on the free plan too. | CNo store rating on record. You add your accounts and server settings yourself. |
| Platforms and integrations | BiPhone, Android, Mac, Windows and Linux, plus links to Slack, Notion, Linear, Trello, Asana and the big cloud drives. The gap is the browser: no web version is listed. | DAndroid only: no iPhone, desktop or web version is listed. |
| Best for | one free inbox on every device you own | an open-source Android email client |
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: BlueMail and K-9 Mail. How we grade
Price against what you get
BlueMail starts at $3 a month when paid by the year and scores 3.0 out of 4 on features, ease of use and platforms. K-9 Mail has no paid plan and scores 2.0.
BlueMail scores higher, and starts $3 a month higher: the question is whether the extra is worth that to you. Of the other email apps on the chart, 2 score higher than BlueMail for less, and none scores higher than K-9 Mail for less.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Where they differ
- BlueMail is end-to-end encrypted, according to its own site.
- K-9 Mail is open source, according to its own site.
- BlueMail also covers templates, calendar and inbox filtering.
At a glance
| BlueMail | K-9 Mail | |
|---|---|---|
| Pricing | Free plan | Free |
| Starts at | $35.99 per year (Plus, shown as $3 per month billed annually) | Free |
| Free plan | Personal plan, free for individual use: unlimited email accounts, unified inbox, Clusters, MagicSync and PGP encryption on every platform. GemAI and desktop email backup are not included. | Free to download from Google Play, F-Droid, GitHub Releases or Amazon; no paid plans are listed. |
| Free trial | 7-day free trial of Plus (annual subscriptions, per the FAQ) and 14-day free trial of Team | None listed |
| macOS | ||
| Windows | ||
| Linux | ||
| iOS | ||
| Android | ||
| Made by | Blix Inc. | K-9 Mail |
| Price read from | bluemail.me | k9mail.app |
| Checked | Oct 5, 2026 | Nov 13, 2026 |
Worth knowing
BlueMail
- GemAI, email backup on desktop and priority support need the paid Plus plan; S/MIME, SSO and MDM support are listed only on Enterprise.
- No web version is listed: BlueMail runs as apps for iOS, Android, macOS, Windows and Linux.
- The pricing page shows yearly prices as a rounded monthly figure ($3 and $8) and switches currency by country; the figures here come from its US price table.
- The US App Store lists BlueMail+ in-app purchases at $6.99 and $49.99 with no billing period shown; the website prices Plus at $4.99 a month or $35.99 a year.
K-9 Mail
- Android only; no iOS, desktop or web version is listed.
- The site's banner says Thunderbird for Android is available now and calls it the future of K-9 Mail.
- It is a client for existing mailboxes and does not provide an email address.
Key features
BlueMail
- Unified Inbox
- Mail from every account and provider appears in one combined view. Every plan, including the free one, allows unlimited email accounts.
- Clusters
- Automatically groups newsletters, transactions, shopping, social and personal mail, so everything in a group can be archived, moved or flagged at once.
- GemAI
- Generative AI that summarizes threads, drafts replies, rewrites text for tone or length and translates across 90+ languages. It is included from the Plus plan.
- Active Screener
- Holds mail from new senders in a review queue, where each sender can be allowed, blocked or sent to spam before reaching the inbox.
- Integrated calendar
- A calendar inside the mail app that syncs with Google, Apple and Outlook calendars and can propose meeting times directly from a thread.
- PGP encryption
- Encrypt, sign and verify messages with PGP keys that you bring or generate inside the app. S/MIME support is listed on the Enterprise plan only.
K-9 Mail
- Push IMAP
- The feature list names push IMAP support, so new messages can arrive without polling on servers that allow it.
- GPG and PGP/MIME
- The site lists GPG and PGP/MIME support for signing and encrypting messages.
- Unified inbox and identities
- A unified inbox, per-account notifications and multiple identities are listed, along with signatures and BCC to self.
- Message handling tools
- Listed tools include message flagging, keyboard shortcuts, attachment saving and emoji support.
- Several ways to install
- The download page offers the Play Store (with a beta channel), F-Droid, GitHub Releases and Amazon.
Plans
BlueMail
Personal$0
For individuals: unlimited email accounts, unified inbox, Clusters, MagicSync, PGP encryption, light and dark themes, and community support.
Plus$35.99
per year (shown as $3 per month), or $4.99 billed monthly
Everything in Personal, plus unlimited GemAI, an email verified badge, premium themes, email backup on desktop and priority support.
Team$99
per user / year (shown as $8 per month), or $12 billed monthly
Everything in Plus, plus a domain verified badge, subscription and billing control, custom domain mailboxes and service configuration.
EnterpriseCustom
Adds identity provider integration (SSO), MDM support, S/MIME, adaptive multi-factor authentication, advanced governance and 24/7 priority support.
K-9 Mail
Free$0
Open source under the Apache License 2.0; the site has a donate link.
Ways to pay less
BlueMail
- Annual discount
Lower price with yearly billing
In the US price table Plus is $35.99 a year against $4.99 a month (about 40% less) and Team is $99 per user a year against $12 a month (about 31% less). The page's toggle advertises a 20% saving.
- Other savings
Volume pricing for Team plans over 100 seats
The pricing FAQ says Team plans with more than 100 seats receive automatic volume pricing, and Enterprise is quoted individually by sales.
K-9 Mail
No public discounts listed.
Common questions
Which is cheaper, BlueMail or K-9 Mail?
As of Nov 13, 2026, K-9 Mail is cheaper to start with: it is free, against $3 a month when paid by the year for BlueMail. BlueMail starts at $35.99 per year (Plus, shown as $3 per month billed annually), and K-9 Mail is free.
Which has a free plan, BlueMail or K-9 Mail?
As of Nov 13, 2026, both BlueMail and K-9 Mail have a free plan.
Which platforms do BlueMail and K-9 Mail run on?
As of Nov 13, 2026, only BlueMail lists macOS, Windows, Linux and iOS apps. Both list an Android app. A platform missing from a listing is one its maker's pages did not mention.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.