PoE Calculator

The PoE Calculator helps estimate whether an Ethernet cable can deliver enough power to your devices after cable resistance, voltage drop, and total load. It works for wiring setups involving cameras, wireless access points, VoIP phones, and other network gear. This tool supports planning for complete PoE deployments before buying switches, cables, or devices.

When designing a PoE network, you can also look at nearby hardware: Network Switches for PoE-enabled ports, Ethernet Cables for cabling quality, and Wireless Access Points for typical PoE-powered devices.

What the PoE Calculator Estimates?

• Supply voltage and cable type to predict voltage drop over cable length.
  

• Delivered power per device and total power for multiple devices.
  

• Whether selected cable and PoE standard can safely run all connected devices.
  

• How many devices you can power before exceeding safe supply limits.
  

These outputs help you size your PoE switch and cabling before installation.

Why PoE Is Useful – and What to Watch For?

Power + data over one cable: This reduces wiring work, especially when installing devices where power outlets are impractical (e.g. ceilings, outdoor cameras, remote walls).

Flexible device placement: You can place wireless access points, IP cameras, and VoIP phones wherever you run Ethernet — no need for separate power wiring.

Standardized power levels. Modern standards like IEEE 802.3af (PoE), IEEE 802.3at (PoE+), and IEEE 802.3bt (PoE++) define how much power each port can supply. 

• PoE (802.3af) supplies up to ~15.4 W at the source, about 12.95 W usable at the device.
  

• PoE+ (802.3at) supports more power — useful for stronger devices like high-performance access points or PTZ cameras.
  

• PoE++ / 4-pair PoE (802.3bt) can power high-draw devices needing more wattage.
  

Cable quality matters: Lower-quality or long cables increase resistance and voltage drop. That can reduce delivered power and cause devices to underperform.

When to Use the PoE Calculator?

Use this tool when planning:

• A new Wi-Fi network with ceiling or outdoor access points.
  

• Security camera deployment over Cat5e/ Cat6 cables.
  

• VoIP phone installations without nearby power outlets.
  

• Mixed PoE devices (access points, cameras, IoT) to check total power load.
  

• Upgrades or expansions — to verify if existing cables and switch will support additional devices.
  

If your installation involves wireless coverage design, you might also use the Wireless Access Point Coverage Calculator.

For cabling or fiber-backhaul work paired with PoE, the Fiber Optic Link Loss Budget Calculator can help plan backbone links.

Tips for Reliable PoE Deployment

• Always choose good-quality Ethernet cable (Cat5e or better) with pure copper conductors.
  

• For long cable runs, calculate voltage drop — high resistance can cause under-voltage at the device end.
  

• Add some safety margin: do not run cables at the maximum power limit continuously.
  

• Group devices by power needs — separate high-power devices if possible.