Calculate PoE power, voltage drop, and cable distance instantly with our PoE Calculator. Find the right PoE switch or injector for any device. Note: Typical PoE. This PoE calculator by PoE-World will calculate the total power required for any device including cable loss by any type or length of cable, over Ethernet or not, it calculates the voltage drop and power required by both the device and the loss in the cable. This includes category cables and connectors typically used in enterprise commercial buildings under various installation conditions and ambient temperatures. It works for wiring setups involving cameras, wireless access points, VoIP phones, and other network gear. What Is Power over Ethernet (PoE)? Power.