Nagios XI vs PRTG Pricing: 3 Year Cost Compared

Nagios XI is cheaper than PRTG from the second year onward at every network size both vendors publish. At 100 devices, PRTG costs $4,296 a year while Nagios XI costs $2,595 up front and $2,104 a year after that, so three years come to $12,888 against $6,803. PRTG only wins in year one, and only for networks of about 8 to 50 devices, where its $2,400 entry license undercuts the $2,595 Nagios one by $195.

That result depends on reading both price lists in full, which most comparisons skip. Nagios prints its yearly renewal on a separate page from its license, and PRTG counts sensors rather than devices. Every figure below comes from the two vendors' own pricing pages in US dollars, and every total is arithmetic you can redo.

How much does Nagios XI cost?

Nagios XI Standard is a perpetual license priced by node: $2,595 for 100 nodes, $4,395 for 200, $6,195 for 300, $7,295 for 400, $8,295 for 500, $11,495 for 750 and $14,995 for 1,000. The first year of Maintenance and Support is included. After that, the yearly renewal runs $2,104 at 100 nodes up to $11,898 at 1,000, between 79% and 84% of the license price. Services, the individual checks you run on a node, are unlimited. The full ladder, the Enterprise add-on and a multi-year calculator are on our Nagios XI pricing breakdown.

How much does PRTG cost?

PRTG Network Monitor is a subscription priced by sensor: $200 a month for 500 sensors, $358 for 1,000, $742 for 2,500, $1,300 for 5,000 and $1,642 for 10,000, all billed annually, with support and updates included. A sensor is one measured aspect of one device, and Paessler's own planning ratio is ten sensors per device, so PRTG 500 covers about 50 devices, not 500. The tier-by-tier detail is on our PRTG pricing page.

Nagios XI vs PRTG at 50, 100, 250, 500 and 1,000 devices

The two products count different things, so the only fair comparison is by device. PRTG's device counts are Paessler's own (500 sensors for about 50 devices, 10,000 for about 1,000), and each Nagios figure is the smallest node license that covers the same number of hosts. Standard edition throughout.

Once the first year is over, a Nagios XI renewal costs between 44.5% and 60.4% of the matching PRTG year at 100 devices and above. At 500 devices the renewal is $6,939 against $15,600, less than half. Over three years, Nagios XI comes to 47% to 66% of the PRTG bill at those sizes.

Is Nagios cheaper than PRTG?

Yes, from year two onward, at every device count from 8 to 1,000 on Paessler's ten-sensors-per-device ratio. We checked every integer device count in that range, not just the five rows above: PRTG is cheaper at 43 of them in year one (8 to 50 devices), and at none of them in year two, three or five. The reason is structural. The smallest paid Nagios license is 100 nodes, so a 30-device shop pays for 70 nodes it does not use, but that overpayment is a one-off, while PRTG charges its full price again every year.

The sensor ratio moves the answer in PRTG's favor if your devices are lightly instrumented. At five sensors per device, which is roughly a ping, a disk, a CPU reading and a couple of interfaces, PRTG stays cheaper in year one all the way up to 200 devices. It still loses by year three at every size, because the Nagios renewal is well under the PRTG subscription at every size. At twenty sensors per device, a well-instrumented server estate, 100 devices need 2,000 sensors, which means PRTG 2500 at $8,904 a year instead of PRTG 1000 at $4,296. Nagios does not care: services on a licensed node are unlimited.

What does each price leave out?

The totals above compare list prices, and each vendor leaves different things off its list.

Nagios XI runs on a Linux server you provide and maintain. It is a powerful tool with a reputation for needing someone who knows it well, and that person's time is the largest cost in most Nagios deployments, larger than the license at small sizes. The Enterprise edition, which adds SLA reports, capacity planning, scheduled reports, bulk modification tools and audit logs, is a flat $2,095 on top of any license plus $1,066 a year to renew. If those audit logs are there to evidence a control you are mapping for an auditor, the software that tracks your compliance obligations and controls usually wants that evidence in one place, so check what format it expects before you pay for the add-on.

PRTG runs on a Windows host you provide, unless you buy PRTG Hosted Monitor, which costs the same money to within $5 a year. Support and updates are inside the subscription. Licenses do not stack: Paessler accepts one license key per server, so outgrowing a tier means upgrading through sales rather than adding a small license alongside. Neither vendor publishes a price above 1,000 devices.

Which is better value for a small network?

For under 50 devices and a one-year horizon, PRTG 500 at $2,400 is the cheaper entry, and PRTG's auto-discovery and Windows installer make it the quicker one to stand up. If you expect to run the tool for two years or more, Nagios XI is cheaper even at that size, because its 100-node license renews for $2,104 while PRTG renews for $2,400. The difference is small, $397 over three years at 50 devices, so at this size the deciding factor should be which one your team can operate, not the price.

For 100 devices and above, the price difference stops being small. Over three years Nagios XI saves $6,085 at 100 devices, $10,607 at 250 and $24,627 at 500, before you count the cost of the Linux expertise it expects. If you already have that expertise, Nagios XI is the cheaper tool by a wide margin. If you would have to hire it, the saving at 100 devices is about $2,000 a year, a small fraction of what that expertise costs, and PRTG's easier operation may well be worth it.

Do you need either one for website monitoring?

Probably not, and it is worth separating the jobs before you size either license. Nagios XI and PRTG are infrastructure monitors. They run inside your network and see servers, switches, disks, services and bandwidth, which no external tool can. They are the wrong place to answer "can customers reach the website right now", for two reasons.

First, both check from wherever their server sits, which is usually inside the network whose public reachability you are trying to test. A DNS error, an expired certificate at the CDN or a regional routing problem can take the site down for customers while the internal probe still gets a clean response. Seeing that requires checks from several locations outside your network. Second, public sites and APIs consume licensed units. Nagios defines a node on its pricing page as "any unique IP or web URL", and on PRTG a website with HTTP, certificate, DNS and ping checks is four or five sensors.

The cheaper split for most teams is to keep the infrastructure monitor for the estate and move the public endpoints to an external uptime tool priced per monitor. On UptimeHub, 100 sites and APIs checked from outside, with SSL and domain expiry alerts and a branded status page, is $29 a month on the Pro plan billed yearly. Other vendors in that category are priced side by side in our uptime monitoring pricing comparison.

How we priced this

Nagios XI license prices come from nagios.com/pricing-plans, the renewal ladder from nagios.com/maintenance-support-plans (which lists its prices as effective from January 1, 2026), and the node and service definitions from the Nagios XI product page. PRTG prices come from paessler.com/pricing, parsed from the rate-card table. The three-year totals assume list prices, the Standard edition, yearly renewal and no tier change. Server hardware, operating system licensing and staff time are excluded for both. The PRTG side uses Paessler's ten-sensors-per-device planning ratio, which is a vendor rule of thumb, not a measurement of your network.