Miles Free

Director of Industry Research and Technology, PMPA

The need frequently arises in our shops to estimate the weight of steel, whether as a part of quoting, to estimate how much steel may be needed given a certain length of part, or to decide how heavy the bar is that we are loading into the machines for safety purposes. Counting bars in a bundle and multiplying by weight per bar allows a quick “reality check” on whether or not the tag weight is correct, or how much weight is left in the rack.

Steel weighs 0.2833 pound per cubic inch. To get the weight of a steel bar, we need to calculate its volume in cubic inches.

To calculate the volume, we need to first calculate the area in square inches of the section, then multiply by its length.

## Square or Flat Bar

To find the area of a square or flat bar, multiply the width by the thickness. Then multiply that by the length (in inches) to calculate the volume, then multiply the volume by 0.2833 pound per cubic inch.

Example: 1-inch square steel bar 12 feet (144 inches) long.

1 inch × 1 inch × 144 inches = 144 cubic inches ; times 0.2833 pounds per cubic inch = 40.97 pounds

Example: ½ inch × 2 inch flat 10 feet (120 inches) long.

½ inch × 2 inches × 120 inches = 120 cubic inches; times 0.2833 pound per cubic inch = 33.99 pounds

## Round Bar

To find the area of a round bar, square the diameter and multiply by 0.7854. Multiply this by the length to calculate the volume.

Example: 1-inch round by 12 feet long steel bar.

1 inch × 1 inch × 0.7854 = 0.7854 square inches × 144 inches = 113.09 cubic inches; × 0.2833 pound per cubic inch = 32.04 pounds per bar

Weight of bars left in a bundle: If there are 75, 1-inch round 12 feet long bars left in a bundle, the weight of the remaining steel is 75 bars times 32.04 pounds per bar = 2,403 pounds

Example: ¾-inch round by 4 feet (48 inches) long steel bar.

0.750 inch × 0.750 inch × 0.7854 × 48 inches = 21.21 cubic inches; × 0.2833 pound per cubic inch = 6.00 pounds

## Hex Bar

To find the area of a hex, first square the flat-to-flat distance, then multiply that by 0.866. Then multiply by length in inches to get the volume. Then multiply by 0.2833 pounds per cubic inch to get the pounds.

Example: 1-inch hex steel bar, 12 feet (144 inches) long.

1 inch × 1 inch × 0.866 × 144 inch × 0.2833 pound per cubic inch = 35.33 pounds

Example 1.5-inch hex bar 3-inch long blank for chucker.

1.5 inches × 1.5 inches × 0.866 × 3 inches × 0.2833 pounds per cubic inch = 1.93 pounds per 3-inch blank