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What is a "sensor" in PRTG?



PRTG licensing is measured by so-called sensors. To purchase the license that fits my needs, I would like to know:

  • What is a sensor?
  • How many sensors do I need for my infrastructure?

definition help important prtg sensor website

Created on Mar 6, 2012 2:00:24 PM by  Daniel Zobel [Product Manager]

Last change on Jun 7, 2021 11:28:52 AM by  Maike Guba [Paessler Support] (2,404) 2 1

4 Replies

Accepted Answer



This article applies to PRTG Network Monitor 19 or later

What is a sensor in PRTG?

Short answer

In PRTG, sensors are the basic monitoring elements. One sensor usually monitors one measured value in your infrastructure, for example, the traffic of a switch port, the CPU load of a server, or the free space of a disk drive.

On average, you need about 5-10 sensors per server or one sensor per switch port.

All licenses of PRTG only differ by the maximum number of sensors that you can use for monitoring. For more information, see also the PRTG price list for details.

Note: When you buy one license now, you can upgrade to a larger one at any time.

More detailed answer

In PRTG, you create devices that represent the actual devices, servers, databases, and more in your network. Then you add sensors to these devices.

About devices and sensors

  • For example, you can create a device that represents your firewall, a device that represents your Exchange server, and a device that represents your printer.
  • To each device, you can add one or more sensors.
  • Each sensor monitors one single aspect of a device. This can be, for example, the Ping time, the CPU load on a server, the traffic of a network interface, or the status of the toner cartridge.

Examples of sensors

For example, when monitoring a firewall, an Exchange server, and a printer, you can use the following sensors:

DevicePossible Sensors *
Interface #01
Interface #02
Interface #03
Interface #04
Interface #05
Interface #06
CPU Idle Percent
UDP Datagrams In
UDP Datagrams Out
SNMP Messages In
SNMP Messages Out
CPU Load Processor 1
CPU Load Processor 2
RAM Memory
Network Card Traffic
Disk Free
MSExchange Mailbox Send Queue Size
MSExchange Mailbox Receive Queue Size
POP3 Round Trip
Fan 1 Speed
Fan 2 Speed
Disk Array
Board Temperature
PRINTERToner Status
Paper Status
Jam Status

* This is meant as an example only. It depends on your device and your network configuration which sensors you can actually use.

How many sensors do I need?

The number of sensors that is necessary for your individual setup depends on how closely you want to monitor your network. It is your decision whether you set up general Ping and Port monitoring for a device, or whether you monitor it very closely, including many different performance parameters.

Note: As a rule of thumb, you can calculate with about 5 to 10 sensors per device.

What types of sensors are available?

There are more than 250 different sensor types available in PRTG. For a complete list, see the PRTG Manual: List of Available Sensor Types.

Created on Mar 6, 2012 2:36:07 PM by  Daniel Zobel [Product Manager]

Last change on Nov 23, 2023 2:47:53 PM by  Jacqueline Conforti [Paessler Support]



I just configured a new environmental temp/humidity sensor. My question is how do I monitor temperature and humidity levels in PRTG? There doesn't appear to be any documentation in this regard.


Created on Nov 14, 2018 6:22:01 PM

Last change on Nov 22, 2018 8:53:13 AM by  Isidora Jeremic [Paessler Support]




Thank you for your KB-post.

Which hardware do you use for monitoring of temperature and humidity / what is a vendor of your sensor?

Created on Nov 15, 2018 1:54:33 PM by  Isidora Jeremic [Paessler Support]




Kindly note that PRTG doesn't have any default sensors that can read data from PCBs.

Some customizations will be necessary here, but that depends on capabilities of the hardware you use.

Depending on the type of output, you can try using some of our Custom sensors or maybe HTTP XML/REST Value Sensor.

Best regards

Created on Nov 22, 2018 1:55:12 PM by  Isidora Jeremic [Paessler Support]

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