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Tenable Nessus vs. Qualys VMDR: Which One Actually Fits Your Cybersecurity Consulting Firm?

The $100/mo gap between these two is almost beside the point. The real question is whether you're selling one-time assessments or ongoing managed vulnerability-management retainers — because that's what each platform is actually built around.

By The StackMatch Research Team

Tenable Nessus $500/mo vs. Qualys VMDR $600/mo — the real split is one-time assessments vs. managed retainers

$500/moTenable Nessus (3-100 emp)
$600/moQualys VMDR (3-150 emp)
$1,100/moCost of running both

Pricing for vulnerability scanning platforms serving client engagements.

Monthly cost comparison

Both platforms find the same category of problem — unpatched systems, misconfigurations, exposed services — so a feature-by-feature bake-off mostly ties. The decision that actually matters is what kind of engagements make up your book: point-in-time pentests and annual assessments, or ongoing managed vulnerability-management retainers where a client pays you monthly to keep watching their environment.

Tenable Nessus: $500/mo — built for 3-100 employees

Nessus is the workhorse scanner: point it at a client's environment, get a prioritized list of unpatched systems and misconfigurations, hand the findings to PlexTrac for reporting. It's licensed and priced around discrete scans rather than continuous asset monitoring, which is exactly the shape of a one-time or annual engagement. The common mistake with Nessus isn't overspend — it's under-licensing the asset ceiling for a single large client engagement, forcing a mid-contract true-up call with the vendor right when a deliverable is due.

CostFit

The Tenable-vs-Qualys decision weighs engagement type against asset volume, not which platform has more dashboards.

Qualys VMDR: $600/mo — built for 3-150 employees

Qualys costs $100/mo more because it's a genuinely different product shape: cloud-native, built for continuous monitoring and detection/response across a client's asset inventory rather than a single scan window. That's real value for a firm selling always-on managed vulnerability-management retainers, where the client expects new exposures flagged the week they appear, not at the next quarterly scan. The common mistake is the mirror image of Nessus's: paying for Qualys's continuous-monitoring tier on a client roster that only ever buys one-time assessments, which means paying every month for a capability nobody's using between engagements.

Fit comparison

CriterionTenable NessusQualys VMDR
Team size range3-1003-150
Monthly cost$500$600
Point-in-time vulnerability scanning
Continuous monitoring & detection/response
Best suited forAnnual/one-time assessmentsOngoing managed retainers
Feeds PlexTrac reporting

Running both Nessus and Qualys VMDR simultaneously means $1,100/mo in duplicate scanning spend — and your team spends more time managing two consoles than actually running engagements.

The actual decision rule

you are here5122250+

Asset inventory size and client mix — not a fixed employee threshold — decide when Qualys earns its premium.

  • If your engagements are mostly one-time pentests and annual compliance-driven scans, Tenable Nessus covers the job at $100/mo less and doesn't leave a monitoring tier idle between engagements.
  • If a meaningful share of revenue comes from managed vulnerability-management retainers — clients paying monthly for ongoing coverage — Qualys VMDR's continuous monitoring is the actual product you're selling, not a nice-to-have.
  • If you're straddling both models today, standardize new retainer clients onto Qualys and keep Nessus for one-off work rather than running full licenses of both across your whole book.
  • Qualys's range extends to 150 employees versus Nessus's 100 — if you're approaching that ceiling with a growing asset inventory across clients, migrating before you're forced to under contract pressure is cheaper than migrating after.

One-time/annual assessment book → Tenable Nessus ($500/mo). Managed retainer book, or approaching a 100+ employee client asset footprint → Qualys VMDR ($600/mo) earns its premium through continuous monitoring.

Questions to ask before choosing a scanning platform

  • What share of our current contracts are one-time versus ongoing managed retainers?
  • Would our clients actually notice — or pay more — for continuous monitoring versus quarterly scans?
  • How many concurrent client asset inventories are we scanning today, and how fast is that growing?
  • If we standardize on one platform, which active clients specifically require the other, and what's the migration timeline?

A lot of "best vulnerability scanner" content online is written by, or paid by, the vendor with the bigger affiliate budget — which tends to be the more expensive platform. That's exactly the incentive our engine is built to be blind to; it ranks purely on fit for your engagement mix, not on which vendor pays the biggest bounty.

Run the free audit with your real headcount and current spend to see which one — plus the rest of your stack — actually fits.

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