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Cybersecurity · head to head

Microsoft Sentinel vs Tenable Nessus

Microsoft Sentinel logo

Microsoft Sentinel

Cybersecurity

Cloud-native SIEM and SOAR solution

From
Free
Rated
-
Full reviewWebsite
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Microsoft Sentinel billing is driven by the volume of log data ingested per day, so cost scales with log noise rather than with users or protected assets; Tenable Nessus nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • They diverge on capability: Microsoft Sentinel covers AI-powered analytics, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Microsoft Sentinel and Tenable Nessus actually diverge.

Attributes where Microsoft Sentinel and Tenable Nessus differ
AttributeMicrosoft SentinelTenable Nessus
Pricing modelusage-basedsubscription
PlatformsWeb, ApiWindows, Linux, Macos, Cloud
Founded19752002

Identical on both: starting price (Free), free tier (Yes), 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 Sentinel

  • AI-powered analytics
  • Fusion detection
  • UEBA
  • Automated response playbooks
  • Threat intelligence
  • Hunting queries
  • Workbooks
  • Incident management

Only in Tenable Nessus

  • Network scanning
  • Vulnerability detection
  • Configuration assessment
  • Malware detection
  • Compliance checking
  • Cloud security assessment
  • Mobile scanning
  • API access

Both cover

  • AWS
  • Google Cloud
  • ServiceNow
  • ISO 27001

What people use each for

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

Microsoft Sentinel

  • Cloud-based security information and event management (SIEM)not Tenable Nessus
  • Extended detection and response (XDR) across enterprise infrastructurenot Tenable Nessus
  • Data ingestion and long-term security analyticsnot Tenable Nessus

Tenable Nessus

  • Vulnerability scanning of servers, network devices and web applicationsnot Microsoft Sentinel
  • Configuration and compliance auditing against hardening benchmarksnot Microsoft Sentinel
  • Point in time assessments by consultants and penetration testersnot Microsoft Sentinel

Where each one falls short

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

Microsoft Sentinel

  • Billing is driven by the volume of log data ingested per day, so cost scales with log noise rather than with users or protected assets
  • Commitment tier discounts require reserving daily ingestion capacity in advance, and a tier cannot be downgraded until 31 days have passed
  • Commitment tiers start at 100 GB per day, above what smaller estates ingest
  • Charges for Log Analytics, Logic Apps and Machine Learning are billed separately on top of Sentinel itself
  • The free allowance is only up to 5 MB per user per day for selected Microsoft 365 security logs
  • Promotional commitment pricing is time limited and locks in only until a stated end date

Tenable Nessus

  • Nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • Support beyond the base entitlement costs an extra $400 per year for Advanced Support with 24x365 phone and chat access
  • The on demand training course is a separate $275 purchase for a single person for one year
  • Multi year discounts require paying for two or three years up front

Pricing, plan by plan

Microsoft Sentinel

Free
  • Pay-As-You-Go$2.46/day
    • Per GB ingested
    • 90-day retention
    • First 31 days free for new workspaces
  • Commitment TiersFree
    • 100GB to 50TB tiers
    • Up to 65% discount
    • Predictable billing
  • Microsoft 365 E5Free
    • Free data ingestion for M365 logs
    • Bundled with E5 license

Tenable Nessus

Free
  • Nessus EssentialsFree
    • Up to 16 ips
    • Network scanning
    • Vulnerability assessment
  • Nessus Professional$2600/year
    • Unlimited targets
    • Enterprise features
    • Advanced analytics
  • Nessus Expert$5200/year
    • All Professional features
    • Cloud integration
    • Advanced reporting

Which should you pick?

Choose Microsoft Sentinel if

  • You need ai-powered analytics.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want fusion detection.
Microsoft Sentinel review

Choose Tenable Nessus if

  • You need network scanning.
  • You want to start without paying.
  • You work on Windows, Linux, Macos, Cloud.
  • You also want vulnerability detection.
Tenable Nessus review

Questions people ask

Is Microsoft Sentinel or Tenable Nessus better?
Neither clearly leads. Microsoft Sentinel starts at Free and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Microsoft Sentinel or Tenable Nessus?
Microsoft Sentinel starts at Free and Tenable Nessus at Free.
Does Microsoft Sentinel or Tenable Nessus run on more platforms?
Microsoft Sentinel runs on Web, Api. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Microsoft Sentinel for free?
Both have a free tier, so you can try either at no cost before committing.
What is Microsoft Sentinel best used for?
Microsoft Sentinel is most often used for cloud-based security information and event management (siem), extended detection and response (xdr) across enterprise infrastructure, data ingestion and long-term security analytics. Of those, cloud-based security information and event management (siem) and extended detection and response (xdr) across enterprise infrastructure are not what Tenable Nessus is typically brought in for.
What can Microsoft Sentinel do that Tenable Nessus cannot?
Microsoft Sentinel covers AI-powered analytics, Fusion detection, UEBA, Automated response playbooks. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection. Both handle AWS, Google Cloud, ServiceNow, ISO 27001.

Answered from the vendors’ own pages

Microsoft Sentinel: How is Microsoft Sentinel pricing calculated?

Microsoft Sentinel uses a pay-as-you-go usage-based model where you pay only for data ingested, stored, and consumed. Flexible commitment tiers are available to reduce total cost of ownership, with specific rates not published on the public pricing page. Source: https://www.microsoft.com/security/business/siem-and-xdr/microsoft-sentinel/

Source
Tenable Nessus: What are the three Nessus offerings?

Nessus Essentials is a free introductory offering for educators, students, and career starters, limited to 16 IPs for scanning. Nessus Professional is designed for consultants and SMBs, providing unlimited IT scans across any location. Nessus Expert is the premium offering extending Professional with web application scanning, infrastructure-as-code scanning, and external attack surface assessment up to 5 domains.

Source
Microsoft Sentinel: Does Microsoft Sentinel require an Azure subscription?

Yes, Microsoft Sentinel requires a Microsoft Azure subscription to operate. Pricing is handled through Azure and varies based on data consumption and the commitment tier you select. Source: https://www.microsoft.com/security/business/siem-and-xdr/microsoft-sentinel/

Source
Tenable Nessus: What OS platforms does Nessus support?

Nessus runs on Debian/Kali Linux, Fedora, FreeBSD, Mac OS X, Red Hat/CentOS, SUSE Linux, Ubuntu, and various Windows versions including Server 2008, 2012, and Windows 7-10.

Source
Tenable Nessus: Can I use Nessus to scan third-party networks as a consultant?

Yes, Tenable permits you to use Nessus to scan third-party networks. Nessus Professional is ideal for consultants.

Source
Tenable Nessus: Can Nessus perform PCI external scanning?

Yes, you can use Nessus Professional to perform external network scans as required by the PCI DSS 11.2.2 requirement.

Source
Tenable Nessus: What additional features does Nessus Expert provide?

Web application scanning, which is dynamic application security testing (DAST) providing comprehensive visibility and insight into web application security issues; scanning code repositories for vulnerabilities; and assessing external attack surface with subdomain discovery.

Source
Tenable Nessus: What support options exist for Nessus Professional?

Standard Support includes software upgrades, patches, plugin access, and 24x7 support via chat and community portal. Advanced Support adds 24x7 phone access and committed SLAs: P1 less than 2 hours, P2 less than 4 hours, P3 less than 12 hours, P4 less than 24 hours.

Source
Tenable Nessus: How frequently are Nessus plugins updated?

Nessus plugins are updated daily, based on when vendors and security research sites publish new vulnerabilities.

Source
Tenable Nessus: How does licensing work in virtual machine environments?

Whether you are using Nessus in a physical or a virtual environment, the IP addresses or hosts that you are scanning from must be licensed.

Source
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