Formulas & Data
SHAPE WEIGHT FORMULAS
The following shape formulas can be used to calculate the nominal weights for various carbon steel shapes. These weight calculations are based upon the theoretical weight of steel at 40.80 pounds per square foot per one inch of thickness. These weight formulas are for nominal weights, (and are approximations), and should not be considered an exact weight. All dimensions are to be in inches.
Rounds = 
Diameter squared x 2.67 = Weight in pounds per Linear Foot. 
Squares = 
Diameter squared x 3.4 = Weight in pounds per Linear Foot. 
Hexagons* = 
Diameter squared x 2.945 = Weight in pounds per Linear Foot. 
Octagons* = 
Diameter squared x 2.817 = Weight in pounds per Linear Foot. 
Plates, Sheets & Flats = 
Thickness x Width x 3.45 = Weight in pounds per Linear Foot. 
Plate Circles = 
Diameter squared x thickness x .2225 = Weight per Circle. 
Round Tubing = 
10.68 x (O.D. – W.T.) x W.T. 
Square Tubing = 
13.6 x (O.D. – W.T.) x W.T. 
Rectangular Tubing = 
13.6 x [(SL + SS) – W.T.] x W.T. 
* Diameter is measured across the flats.
O.D. = Outside Diameter W.T. = Wall Thickness SL = Long Side SS = Short Side


GENERAL FORMULAS
Cost per Hundred Feet = 
Cost per Hundred Weight x Weight per Foot. 
Cost per Hundred Weight = 
Cost per Hundred Feet / Weight per Foot. 
Area of a Circle = 
Diameter x Diameter x 0.7854 
Circumference of a Circle = 
Diameter x 3.1416 
Diameter of a Circle = 
Circumference x 0.31831 
Area of a Triangle = 
Base x Perpendicular Height x 0.5 
Area of a Rectangle = 
Width x Length 
Area of a Square = 
Side x Side 
Area of Parallelogram = 
Base x Altitude 
Side of an Inscribed Equal Square for a Circle = 
Diameter x 0.8862 
Side of a Square x 1.4142 = 
Diameter of Circumscribed Circle 
Doubling the Diameter of a Circle increases the area of the Circle four times. 
Doubling the diameter of a Pipe increases its capacity four times. 

METRIC CONVERSION FORMULAS
Millimeters x .03937 = Inches 
Inches x 25.40 = Millimeters 
Meters x 3.2809 = Feet 
Feet x .3048 = Meters 
Kilometers x .621377 = Miles 
Miles x 1.6093 = Kilometers 
Liters x 61.023 = Cubic Inches 
Cubic Inches x .01639 = Liters 
Liters x .26418 = U.S. Gallons 
U.S. Gallons x 3.7854 = Liters 
Grams x .03527 = Ounces 
Ounces x 28.350 = Grams 
Metric Ton x .9072 = U.S. Ton 
U.S. Ton x 1.1023 = Metric Ton 
Metric Ton = 2205# 
