The weight of a steel bar is calculated depending on its shape. Its weight per cubic inch is 0.2904 pounds. The weight of a square bar in pounds per foot is calculated by multiplying 3.40 pounds by L squared, where L is the length of one of the sides.
The weight of a round bar is calculated by multiplying the bar's diameter in inches squared by 2.67 pounds. The weight of a hexagonal bar in pounds per foot = D squared x 2.9473, where "D" is the distance between two of its flat sides. The weight of a flat bar = thickness x width x 3.40 pounds; all length measurements are in inches.