Cable Length Calculator

Tools - Pcbcupid - Free and easy to use Cable Length Calculator

The linear distance that a cable, wire, or transmission line in an electrical or electronic circuit or system covers is referred to as its length.
It is commonly measured in quantities like meters, feet, or kilometers and is expressed from the cable’s starting point to its termination point.

The primary purpose of cable length measurement is to determine the physical distance required for the installation and connection of cables in electrical and electronic systems.
Cable length aids in planning and constructing electrical layouts, determining the quantity of cable necessary for installations, and ensuring proper cable management inside systems.


  • Networking and Telecommunications
  • Power Distribution
  • Audio and Video Installations
  • Industrial Automation

The online calculator provided helps calculate the length of a cable or conductor while considering the natural sag that occurs in cables. When a cable is suspended between two points, its inherent flexibility causes it to form a parabolic shape. Consequently, the length of the cable between the two points exceeds the original distance. This calculator utilizes the cable span and sag to determine the length of the cable or conductor accurately.

Understanding Cable Length:

There are a number of things to take into account when choosing an electrical cable’s length. The following are important things to remember: 

Maximum Cable Length: A cable’s maximum length varies depending on its type and technology. For instance, the maximum length of an HDMI cable is 10 meters (32.8 feet) and the maximum length of a USB cable is 5 meters (16.4 feet) for devices that use USB 2.0. 

Cable Type: The length of the cable may vary depend on the kind used. Twisted pair cables are more appropriate for shorter distances, whereas coaxial cables are intended for greater ones, with a maximum length of 100 meters (328 ft). 

Signal Quality: The length of the cable has an impact on the signal’s quality as well. Errors or data loss may arise from a decline in signal strength and quality as cable length grows. 

Shielding: Although shielding can lessen interference and enhance signal quality, flawless signal transmission cannot be guaranteed. The kind of shielding employed and the signal’s frequency determine how effective the shielding is. 

Connectors: The length of the cable may also depend on the type of connections that are utilized. For instance, over longer lengths, connectors with smaller pins could be more vulnerable to breakage or disconnection.

Cable Quality: Another crucial factor is the cable’s actual quality. While a low-quality cable may deteriorate fast, a high-quality cable with a sturdy design and appropriate shielding can tolerate extended lengths and maintain signal quality. 

Application: The length of the cable is also dependent on how it is used. A cable used for a long-distance connection, for instance, would not need to be as high-quality as one used for a short-distance connection between two devices.

In conclusion, a variety of elements, such as the type of cable, signal quality, shielding, connections, cable quality, and application, affect how long an electronic cable is. 

Note : Don’t end with comma ( , )

Cable Span (S)
Cable Sag (d)
Result unit


\[L=S+ \frac{8d^2}{3S}\] ​

where :

  • L = Cable Length
  • S = Cable Span
  • d = Cable Sag

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