Best Spam Filters and Add-Ins for Outlook (2026)

What is the best spam filter for Outlook?#

For most people, the best spam filter for Outlook is the one already in it: the junk filter, your Blocked Senders list, and the built-in Report button. It is free, works in new Outlook, classic Outlook, Outlook on the web and the mobile apps, and every report sends a signal back to Microsoft. Buy a third-party tool only to close a specific gap.

A note on words: this page says spam, and Outlook calls it junk. They mean the same thing here. The apps, software and plugins below fall into four shapes, and the shape matters more than the feature list: an add-in inside Outlook, a service that works on your mailbox, a gateway your IT admin runs for the whole company, or a desktop program that checks mail before Outlook downloads it.

The category also changed under everyone's feet. Microsoft put its own Report Message and Report Phishing add-ins into maintenance mode and points admins to the built-in Report button instead, and new Outlook for Windows does not run the classic COM and VSTO add-ins that most older anti-spam plugins were built on. If you want the background on that second change, see why COM add-ins stop working in new Outlook.

Which one is right for me?#

• One person on Outlook.com or Microsoft 365, a few junk messages a week: Outlook's junk filter, Blocked Senders and the Report button. Spend nothing.
• Your junk is really mailing lists you once signed up for: Clean Email (bulk unsubscribe) or SaneBox (moves low-priority mail out of the inbox and blocks senders for good).
• You plan to stay on classic Outlook for Windows: a classic add-in like SpamBully still works there, but it will not follow you to new Outlook.
• You want to see and delete mail on the server before Outlook downloads it, or you use a POP3 account: MailWasher Pro.
• You run IT for a Microsoft 365 company and Microsoft's own filtering is not stopping enough: Barracuda Email Protection or Hornetsecurity 365 Total Protection.

Outlook spam filters compared#

How we compared#

• Each tool was checked against its vendor's own page or Microsoft's documentation in October 2026: does it still ship, does it work in new Outlook for Windows, and what shape is it.
• No competitor prices. Packaging changes often, so each entry gives the shape (free version, trial, plans) and the vendor page to check for today's price.
• Where a vendor page did not answer a question, we say so rather than guess.

1. Outlook's built-in Report button (Microsoft)#

Not a third-party tool, but it belongs at the top. Microsoft's Defender for Office 365 documentation says the Report Message and Report Phishing add-ins are in maintenance mode and will eventually be deprecated, and recommends the built-in Report button instead. Select one or more messages, choose Report, then Report junk or Report phishing. Junk reports move the message to the Junk Email folder and add the sender to your Blocked Senders list; phishing reports delete the message. In the Junk Email folder, Report then Not junk moves mail back to the Inbox. In a work account, your admin decides whether reports also go to Microsoft, to an internal mailbox, or both.

Microsoft lists the button in new Outlook for Windows, Outlook on the web, current builds of Outlook for Microsoft 365 (classic), Outlook for Mac 16.89 or later, and recent versions of Outlook for iOS and Android. Where it falls short: it does not unsubscribe you from lists, and it does not give you a queue of borderline mail to sweep. For tuning the filter itself, see is Outlook's junk filter good enough.

• Best for: anyone, as the first step.
• Works in new Outlook: yes.
• Pricing shape: included.
• Not for: bulk unsubscribing or company-wide policy beyond what your admin configures.

2. SaneBox#

SaneBox is not an add-in. It connects to your mailbox and moves messages into folders it creates, such as SaneLater for low-priority mail and SaneBlackHole for senders you never want to see again. Drag a sender into SaneBlackHole once and their future mail goes there instead of your inbox. Because the work happens on the mailbox, the result shows up the same way in new Outlook, classic Outlook, the web and the mobile apps.

SaneBox lists a 14-day trial and three plans separated by how many accounts and features you get; check sanebox.com/pricing for the current price. It is the right pick when your problem is too much legitimate but low-value mail, and you want the fix to survive whichever Outlook you end up using.

• Best for: noisy inboxes where most of the clutter is not hostile spam.
• Works in new Outlook: yes, because it is not inside Outlook.
• Pricing shape: 14-day trial, then paid tiers.
• Not for: phishing defence for a whole company.

3. Clean Email#

Clean Email is an Outlook email cleaner that works on your account, not inside the app. It groups mail into bundles you can archive, delete or unsubscribe from in bulk. Its Unsubscriber sends unsubscribe requests for you and can block senders who ignore them, and Auto Clean turns a one-off sweep into a standing rule. That matters because a lot of what Outlook users call junk is mail they once opted into.

Clean Email's help centre says free use covers cleaning up to 1,000 messages, with premium features such as Auto Clean on a paid subscription and a temporary premium trial. Check clean.email for current plans. For more tools in this shape, see our bulk unsubscribe tools for Gmail and Outlook.

• Best for: a backlog of newsletters and promotions.
• Works in new Outlook: yes, because it is not inside Outlook.
• Pricing shape: limited free use, then paid.
• Not for: blocking targeted phishing.

4. Barracuda Email Protection#

Barracuda's product for Microsoft 365 connects through the Microsoft 365 API, with no MX record change according to the vendor page, and filters at the company level. Its clawback feature removes a threat from every mailbox it landed in after delivery, which Outlook's own filter cannot do from the user side.

Because filtering happens upstream, it works with every Outlook your staff use. The site offers a free trial and a free threat scan; pricing comes through Barracuda. Pick it if you run a Microsoft 365 tenant, users keep complaining about spam that Microsoft's filtering lets through, and you have enough seats to justify a company-wide service.

• Best for: IT admins who need post-delivery removal.
• Works in new Outlook: yes.
• Pricing shape: business plans; trial on request from the site.
• Not for: one person with a personal Outlook.com account.

5. Hornetsecurity 365 Total Protection#

Hornetsecurity's 365 Total Protection is the same company-level shape as Barracuda: a service for Microsoft 365 that filters spam and malware before delivery, managed from Hornetsecurity's console rather than from inside Outlook.

It is sold as four stacked plans. Plan 1 covers spam and malware filtering, encryption and signatures; Plan 2 adds advanced threat protection, continuity and archiving; Plan 3 adds Microsoft 365 backup; Plan 4 adds security awareness training, permission management and DMARC tools. The page does not publish prices, so you request them. Pick it if you also want backup or archiving from the same vendor.

• Best for: IT admins who want filtering plus backup or archiving in one contract.
• Works in new Outlook: yes.
• Pricing shape: four plans, priced on request.
• Not for: individual users.

6. MailWasher Pro (Firetrust)#

MailWasher Pro is a desktop program, not an add-in. It checks your mail on the server before Outlook (or any other client) downloads it, shows each message as plain text with real link destinations, and lets you delete the bad ones first. Firetrust lists support for POP3 and IMAP, including Outlook.com and Microsoft 365, with OAuth sign-in for Outlook.com.

If your mailbox already has strong server-side filtering, that preview step adds less. It earns its place for POP3 accounts on older hosts and for people who want to see mail before it touches their PC. Firetrust offers a free version and a Pro version sold as a yearly or lifetime licence, with a 30-day money-back guarantee.

• Best for: POP3 users and anyone who wants a preview-and-delete step.
• Works in new Outlook: not applicable; it runs beside your client.
• Pricing shape: free version, paid Pro licence.
• Not for: company-wide filtering.

7. SpamBully#

SpamBully is here as the honest example of a classic Outlook add-in. Its site says it works with Office 365, Office 2021 and older Outlook versions, and it installs into classic Outlook for Windows. It does not run in new Outlook, because Microsoft's documentation says new Outlook for Windows does not support COM or VSTO add-ins at all; only web add-ins run there.

Staying on classic Outlook is still a real option: Microsoft said in March 2024 that it will keep honouring support timelines for existing versions of classic Outlook for Windows until at least 2029. Just treat any classic anti-spam add-in as tied to classic Outlook unless the vendor says otherwise.

• Best for: people who have decided to stay on classic Outlook.
• Works in new Outlook: no.
• Pricing shape: trial, then a paid licence.
• Not for: new Outlook, Outlook on the web or Mac.

Tools you will see on other lists#

SPAMfighter shows up on many Outlook spam blocker lists. Its own compatibility page names Outlook versions from 2000 to 2016 and says nothing about new Outlook, so treat it as a classic-only option. SpamTitan also appears often, but it is a cloud or on-premise email security gateway that sits in front of Microsoft 365, not a desktop add-on; it belongs in the same bucket as Barracuda and Hornetsecurity, and you buy it as a business.

If you want a broader Windows list that is not tied to Outlook, see our guide to spam filter software for Windows.

A separate option: AI Emaily#

AI Emaily is not an Outlook add-in. It is a separate mail client (web, macOS and Windows apps, and iOS) that connects to your Microsoft 365 or Outlook.com account through Microsoft Graph. Your mail stays in your Microsoft mailbox. Every message is scored for spam and phishing on our servers when it syncs, using sender authentication (SPF, DKIM, DMARC), impersonation signals, scam wording and risky links, and anything over the line goes to a Spam folder with a plain-English reason. A separate cold-email filter catches unsolicited sales outreach and lets you block it, batch it into a weekly digest, or allow it, per sender or per domain.

It is the wrong answer if you cannot change email client, or if you need a policy your admin pushes to a thousand seats. We build AI Emaily, so weigh this section with that in mind.

One concession#

For a button inside Outlook that reports junk and blocks the sender, Microsoft's built-in Report button beats everything on this list, including AI Emaily, which is not an Outlook button at all. If that button is all you need, buy nothing. The other tools earn their place only when you need something it does not do: bulk unsubscribing, company-wide filtering and clawback, previewing mail before download, or a different inbox altogether. To handle a single persistent sender, start with how to block a sender in Outlook.