Is Microsoft Defender or Nessus better?

Neither clearly leads. Microsoft Defender starts at $12/month and Nessus at $4790/year, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.

Which is cheaper, Microsoft Defender or Nessus?

Microsoft Defender starts at $12/month and Nessus at $4790/year.

Does Microsoft Defender or Nessus run on more platforms?

Microsoft Defender runs on Web. Nessus runs on Desktop, Api.

What is Microsoft Defender best used for?

Microsoft Defender is most often used for endpoint security and threat protection, identity and access security, email threat protection, saas application security monitoring. Of those, endpoint security and threat protection and identity and access security are not what Nessus is typically brought in for.

What can Microsoft Defender do that Nessus cannot?

Nessus covers Vulnerability scanning, Configuration auditing, Malware detection, Web application scanning.

Cybersecurity · head to head

Microsoft Defender vs Nessus

Microsoft Defender

Cybersecurity

Always-on protection for you and your family's data and devices

From: $12/month
Rated: -

Full review Website

Nessus

Cybersecurity

The most trusted vulnerability assessment solution

From: $4790/year
Rated: -

Full review Website

The short version

Each has a real cost: Microsoft Defender defender Suite requires existing Microsoft 365 E3 or equivalent base licensing; Nessus nessus Professional is $4,790 for one year, with no free or low cost commercial tier
Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Microsoft Defender and Nessus actually diverge.

Attributes where Microsoft Defender and Nessus differ
Attribute	Microsoft Defender	Nessus
Starting price	$12/month	$4790/year
Platforms	Web	Desktop, Api
Founded	Unknown	2002

Identical on both: pricing model (subscription), free tier (No), user rating (Not yet rated), category (Cybersecurity).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Microsoft Defender

Nothing recorded that Nessus does not also cover.

Only in Nessus

Vulnerability scanning
Configuration auditing
Malware detection
Web application scanning
Cloud scanning
Compliance checks
Patch auditing
Pre-built policies

What people use each for

The jobs each tool is most often brought in to do.

Microsoft Defender

Endpoint security and threat protectionnot Nessus
Identity and access securitynot Nessus
Email threat protectionnot Nessus
SaaS application security monitoringnot Nessus

Nessus

Vulnerability scanning for individual practitionersnot Microsoft Defender
Enterprise vulnerability managementnot Microsoft Defender
Web application security assessmentsnot Microsoft Defender

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Microsoft Defender

Defender Suite requires existing Microsoft 365 E3 or equivalent base licensing
Some Defender products use pay-as-you-go pricing with variable costs
Prices vary based on Microsoft agreements, requiring sales contact for custom quotes

Nessus

Nessus Professional is $4,790 for one year, with no free or low cost commercial tier
Multi year terms are the only discount route, at $9,330.95 for two years and $13,637.54 for three
It is a single user scanner, so team workflows mean migrating to another Tenable product
Tenable One vulnerability management is priced separately, starting at $3,500 a year for 100 assets

Pricing, plan by plan

Microsoft Defender

$12/month

Microsoft Defender Suite$12/month
- Endpoint protection
- Identity threat detection
- Email security
Microsoft 365 E5 with Defender$60/month
- Includes Defender Suite
- Microsoft Teams included
- Comprehensive security and compliance
Microsoft Defender Vulnerability Management Add-on$2/month
- Vulnerability scanning and management
- One-month free trial available
- Annual commitment required

Nessus

$4790/year

Nessus Professional$4790/year
- 1 year license
- Best for individual security professionals
Nessus Professional 2-Year$9330.95/2 years
- 2 year license with discounted rate vs. annual
Nessus Professional 3-Year$13637.54/3 years
- 3 year license with discounted rate vs. annual
Nessus Expert$6790/year
- 1 year license
- Enhanced capabilities vs. Professional

Which should you pick?

Choose Microsoft Defender if

Nothing in the data separates Microsoft Defender from Nessus on the points above - pick on price and on how each one feels to use.

Microsoft Defender review

Choose Nessus if

You need vulnerability scanning.
You work on Desktop, Api.
You also want configuration auditing.

Nessus review

Questions people ask

Is Microsoft Defender or Nessus better?: Neither clearly leads. Microsoft Defender starts at $12/month and Nessus at $4790/year, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Microsoft Defender or Nessus?: Microsoft Defender starts at $12/month and Nessus at $4790/year.
Does Microsoft Defender or Nessus run on more platforms?: Microsoft Defender runs on Web. Nessus runs on Desktop, Api.
What is Microsoft Defender best used for?: Microsoft Defender is most often used for endpoint security and threat protection, identity and access security, email threat protection, saas application security monitoring. Of those, endpoint security and threat protection and identity and access security are not what Nessus is typically brought in for.
What can Microsoft Defender do that Nessus cannot?: Nessus covers Vulnerability scanning, Configuration auditing, Malware detection, Web application scanning.

Answered from the vendors’ own pages

Microsoft Defender: How much does Microsoft Defender Suite cost?

Microsoft Defender Suite costs $12/user/month (paid yearly), but requires existing Microsoft 365 E3 or equivalent base licensing. It includes endpoint protection, identity threat detection, email security, and SaaS application monitoring.

Source

Nessus: What is the cheapest Nessus option?

Nessus Professional starts at $4,790 per year for a 1-year license. Multi-year commitments offer discounts, with 2-year licenses at $9,330.95 and 3-year licenses at $13,637.54.

Source

Microsoft Defender: What add-ons are available for Microsoft Defender?

Microsoft Defender Vulnerability Management Add-on costs $2/user/month with annual commitment and includes a one-month free trial. Additional pay-as-you-go products include External Attack Surface Management, Cloud Security Posture Management, and Sentinel.

Source

Nessus: What is the difference between Nessus Professional and Expert?

Nessus Expert costs $6,790 per year for a 1-year license (compared to $4,790 for Professional) and includes enhanced capabilities. Multi-year rates are available at discounted prices.

Source

Microsoft Defender: Is Defender included in Microsoft 365 E5?

Yes, Microsoft Defender Suite is included in Microsoft 365 E5 at $60/user/month (paid yearly with Teams). Prices may vary based on Microsoft agreements, requiring contact with Sales for customized quotes.

Source

Nessus: Does Nessus offer optional support or training?

Yes, Nessus offers add-on services: Advanced Support at $400/year provides 24x365 access to phone, email, community, and chat support. On-Demand Training costs $275/year for Fundamentals course access or $385/year for both Fundamentals and Advanced courses.

Source

Microsoft Defender vs Nessus

Microsoft Defender

Nessus

The short version

Where they differ

What each one covers

Only in Microsoft Defender

Only in Nessus

What people use each for

Microsoft Defender

Nessus

Where each one falls short

Microsoft Defender

Nessus

Pricing, plan by plan

Microsoft Defender

Nessus

Which should you pick?

Choose Microsoft Defender if

Choose Nessus if

Questions people ask

Answered from the vendors’ own pages

Related pages

More on Microsoft Defender

More on Nessus

Keep looking

Other head to heads