How to Calculate Structural Steel Weights

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The weight of structural steel is more than you can determine using a standard scale. Finding the weight of a steel beam requires the use of math equations to properly calculate the weight. To do this, you need to first obtain measurements for the steel beam. Once these measurements are known, you can input them into the equation.

Measure the length of the steel beam with the tape measure and note the measurement, such as 20 feet.

Measure the height of the steel beam and note the measurement, such as 6 inches or 0.5 feet.

Measure the width of the steel beam and note the measurement, such as 6 inches or 0.5 feet.

Multiply the length by the height by the width to calculate the volume of the beam. In this example, this equation looks like (20 x 0.5 x 0.5), for a result of 5 cubic feet.

Multiply the cubic feet of the steel beam by the density of steel. This equation looks like (5 x 490) for a result of 2,450 lbs. This is the weight of the structural steel beam.


  • The density of steel is approximately 490 lbs per square foot. If you use this value, the other measurements you multiply it by need to be in feet, so the units are consistent and you get an accurate weight.



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