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Networking · head to head

Prometheus vs PRTG Network Monitor

Prometheus logo

Prometheus

Networking

Open source monitoring and alerting toolkit for cloud native environments

From
Free
Rated
-
Full reviewWebsite
PRTG Network Monitor logo

PRTG Network Monitor

Networking

Infrastructure monitoring licensed by sensor count, not by device, which changes what a licence actually covers

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Prometheus has a free tier, so it costs nothing to try first.
  • Each has a real cost: Prometheus not suitable for per-request billing as collected data lacks 100% accuracy; PRTG Network Monitor licensing by sensor rather than device means the real cost per device is unpredictable until sensor density is measured; a small network of complex devices can need a much larger tier than device count alone suggests
  • They diverge on capability: Prometheus covers Multi-dimensional Data Model, PRTG Network Monitor covers Sensor-based monitoring.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Prometheus and PRTG Network Monitor actually diverge.

Attributes where Prometheus and PRTG Network Monitor differ
AttributePrometheusPRTG Network Monitor
Starting priceFreeOn request
Pricing modelopen-sourcePer sensor tier, billed monthly on an annual contract
Free tierYesNo
PlatformsLinux, macOS, WindowsWindows, Web, iOS, Android
Founded2015Unknown

Identical on both: user rating (Not yet rated), category (Networking).

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 Prometheus

  • Multi-dimensional Data Model
  • PromQL Query Language
  • Pull-based Collection
  • Service Discovery
  • Alerting Rules
  • Federation
  • Local Storage
  • Grafana

Only in PRTG Network Monitor

  • Sensor-based monitoring
  • Auto-discovery
  • Multiple monitoring technologies
  • Maps and dashboards
  • Cloud and hybrid deployment

What people use each for

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

Prometheus

  • Monitoring and alerting systemnot PRTG Network Monitor
  • Time-series databasenot PRTG Network Monitor
  • Infrastructure metrics collectionnot PRTG Network Monitor

PRTG Network Monitor

  • An IT team wanting network, server and application monitoring in one product rather than assembling separate open source toolsnot Prometheus
  • An organisation that wants a Windows-installable on-premises monitoring server with a polished UI out of the boxnot Prometheus
  • A team sizing a monitoring purchase that needs to calculate sensor density per device carefully before committing to a tiernot Prometheus
  • A company wanting hybrid on-premises and cloud monitoring from the same licence and dashboardnot Prometheus

Where each one falls short

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

Prometheus

  • Not suitable for per-request billing as collected data lacks 100% accuracy
  • Hard limit on scrape body size; large responses cause scrape failure
  • Per-scrape sample limit enforced; exceeding limit marks targets as failed
  • Not designed for long-term durable storage; optimised for metrics collection

PRTG Network Monitor

  • Licensing by sensor rather than device means the real cost per device is unpredictable until sensor density is measured; a small network of complex devices can need a much larger tier than device count alone suggests
  • Different PRTG licence sizes cannot be combined on one server, so outgrowing a tier means a step change to the next tier rather than a smooth incremental add
  • It requires a Windows server for on-premises deployment, which is an added infrastructure and patching burden compared with a Linux-native open source alternative
  • Pricing is materially higher than open source options like Icinga or LibreNMS for comparable core monitoring capability, and the premium is for polish and support rather than unique functionality
  • The free tier (100 sensors) is limited enough that most real deployments quickly need a paid tier, so it functions more as a trial than a genuinely usable free offering
  • Custom sensor scripting and advanced configuration still require real monitoring expertise; the polished UI does not remove the underlying complexity of correctly instrumenting a large network

Pricing, plan by plan

Prometheus

Free
  • Prometheus (Open Source)Free
    • 100% open source
    • Community-driven project
    • Apache 2 License

PRTG Network Monitor

On request
  • PRTG 500$200/month
    • Up to 500 sensors
  • PRTG 1000$358/month
    • Up to 1,000 sensors
  • PRTG 2500$742/month
    • Up to 2,500 sensors
  • PRTG 5000$1300/month
    • Up to 5,000 sensors

Which should you pick?

Choose Prometheus if

  • You need multi-dimensional data model.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want promql query language.
Prometheus review

Choose PRTG Network Monitor if

  • You need sensor-based monitoring.
  • You work on Windows, Web, iOS, Android.
  • You also want auto-discovery.
PRTG Network Monitor review

Questions people ask

Is Prometheus or PRTG Network Monitor better?
Neither clearly leads. Prometheus starts at Free and PRTG Network Monitor at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Prometheus or PRTG Network Monitor?
Prometheus has a free tier; the other does not. Paid plans start at Free for Prometheus and On request for PRTG Network Monitor.
Does Prometheus or PRTG Network Monitor run on more platforms?
Prometheus runs on Linux, macOS, Windows. PRTG Network Monitor runs on Windows, Web, iOS, Android.
Can I use Prometheus for free?
Yes. Prometheus has a free tier, so you can try it without paying. PRTG Network Monitor starts at On request.
What is Prometheus best used for?
Prometheus is most often used for monitoring and alerting system, time-series database, infrastructure metrics collection. Of those, monitoring and alerting system and time-series database are not what PRTG Network Monitor is typically brought in for.
What can Prometheus do that PRTG Network Monitor cannot?
Prometheus covers Multi-dimensional Data Model, PromQL Query Language, Pull-based Collection, Service Discovery. PRTG Network Monitor covers Sensor-based monitoring, Auto-discovery, Multiple monitoring technologies, Maps and dashboards.

Answered from the vendors’ own pages

Prometheus: What does Prometheus cost?

Prometheus is completely free and open source. There are no pricing tiers or paid plans. The entire project is licensed under Apache 2 and hosted on GitHub.

Source
PRTG Network Monitor: Is PRTG licensed per device or per sensor?

Per sensor. Each individually monitored metric counts as one sensor, so a single device is typically several sensors.

Prometheus: Is Prometheus commercial software or free?

Prometheus is 100% open source and community-driven. It is a CNCF graduated project with no commercial restrictions or licensing fees.

Source
PRTG Network Monitor: Can I combine two PRTG licence tiers on one server?

No, Paessler states different license sizes cannot be combined on one PRTG installation.

Prometheus: How is Prometheus licensed?

Prometheus is licensed under the Apache 2 License, which permits free use, modification, and distribution for commercial and non-commercial purposes.

Source
PRTG Network Monitor: Is there a free tier?

Yes, PRTG offers a free tier limited to 100 sensors, which most production networks will exceed quickly.

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