This implies that for every meter of this particular cable, its weight is 400 kg. Calculating the weight per meter is pivotal in infrastructure projects, ensuring that the cables used can support the necessary weight and tension. How to Calculate Cable Weight Per Meter? The. The formula to calculate cable weight per meter is: Where: For example, if you have a copper standard cable weighing 30 lbs and a length of 5 meters, the calculation would be: Scenario: A project requires calculating the weight per meter of a copper standard cable. If you enter a price per kilogram, it also gives you a realistic material cost.