Power Drop Calculator

How to use this tool:

  1. Enter the initial voltage. Choose if your system operates on 12 V or 24 V
  2. Select AC or DC. Choose which voltage type your system utilized. Typical selections are 12 VDC and 24 VAC
  3. Enter the current draw of your camera in amps. Note: 1 amp = 1000 mA. Thus, if your camera draws 300 mA, enter 0.3 into this field
  4. Enter the distance of your cable in feet
  5. Enter the size of your cable. CCTV standard is 18 awg
  6. Click ‘Calculate.’ Click ‘Cancel’ to clear the results and start again.

1. Initial Voltage

2. AC / DC

3. Current (Amps)

4. Cable Length (ft)

5. Cable Gauge (AWG)




Note: Industry standard is a voltage drop of no greater than 10%.

Example 1

At 12 Vdc, a 300 mA camera at 100 feet on standard 18 awg will have a voltage drop of 0.38 volts. Industry standard is +/- 10% which is 1.2 volts. In this example, you are within limits.

Example 2

12 Vdc, 0.8 amps or 800 ma (not unreasonable for an IR camera) at a distance of 150 feet on 18 awg would give you a drop of 1.54 volts, which is greater than acceptable limits. The way to get around this is to have a shorter cable run, or increase the size of your power wire. In this example, increasing the power wire to 16 awg would decrease the voltage drop to 0.96 volts, which is within limits.

Power Usage Calculator

How to use this tool:

Watts = Amps x Volts … also known as … Power = Current x Voltage

Enter any TWO values and press calculate to get the THIRD value:

Volts = Voltage ….. Typically 12V DC

Watts = Power ….. Typical Camera <5W

Amps = Current ….. Typical Camera = 1A or 2A

Example 1

You have a 12 Volt power supply that delivers 1 Amp of current. Fill in the Volts and Amps fields to find the Watts.

Example 2

Your 18 Channel CCTV power supply box is 12V DC that offers 180W. Your cameras each require 0.5A. Will your power supply handle 16 cameras?

  1. Enter 12 under volts
  2. Enter 180 under watts
  3. Click calculate
  4. You get 15 in this example

Your power supply box can handle 15A of current. 16 cameras x 0.5A = 8A leaving plenty of power left over.