Cable Size Calculator

Tools - Pcbcupid - Easy and simplified Cable Size Calculator

The diameter, cross-sectional area, and electrical capacity of cables used in electrical and electronic systems are referred to as cable size.
It includes elements that define the cable’s fitness for a certain application, like insulation type, conductor material, and current-carrying capability.

Ensuring the safe and effective transfer of electrical power within a system is the main goal of cable sizing.
A properly chosen cable size maximizes energy economy and system performance while reducing the risk of overheating, voltage drop, and electrical problems.


  • Building Wiring
  • Industrial Installations
  • Automotive Wiring
  • Telecommunications

The gauge or size of copper or aluminum wires needed for an electrical circuit can be found using this online electrical calculator.

Understanding Cable Size:

There are a number of things to take into account when choosing the right cable size for your particular application. 

Cable Bundling: The total wire size requirements are impacted when many conductors are bundled together because each conductor’s ampacity must be derated. 

Frequency of Operation: The skin effect in AC applications can alter the wire sizing and effective resistance depending on the frequency of operation. 

Resistance: With the exception of superconductors, all conductors have some resistance, which is inversely proportional to the conductor’s diameter and directly relates to its length.

Voltage Drop: Voltage drop, or the loss of electrical potential along a cable run, is influenced by the length of the wire. In Singapore, a cable run’s voltage drop cannot be more than 4% of the supplied voltage. 

Ampacity: A cable’s ampacity, or maximum current-carrying capacity, must be checked to make sure the chosen cable size can support the maximum current that the circuit requires.

It’s also important to consider the following:

Building Regulations:To guarantee adherence to electrical safety standards, familiarize yourself with local construction codes and standards, such as BS7671 in the UK.

Certification: Consult with a licensed electrician to make sure the work is completed in accordance with the necessary requirements and is certified as such.

Cable Types: Consider aspects like insulation, conductor type, and ambient conditions when selecting the right kind of cable for your purpose.

You can be sure that you choose the appropriate cable size for your particular application, guaranteeing safe and dependable operation, by taking these aspects into account and utilizing the appropriate computations and tools.

Note : Don’t end with comma ( , )

Source Voltage (SV)
Number of Phases
Voltage Drop (VD)


For Single Phase

\[Wire\; Circular\; Mils = 2 * Specific\; Resistance * Amperes * Distance / (VD / SV)\]

For Three Phase

\[ Wire\;Circular\; Mils = 2 * 0.866 * Specific \;Resistance * Amperes * Distance / (VD / SV)\]

where :

  • Specific Resistance = 11.2 for Copper Cable
  • Specific Resistance = 17.4 for Aluminium Cable
  • VD = Voltage drop
  • SV = Source Voltage

Any questions? Drop them here!