Air Duct Sizing Calculator

The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct size, weight per linear foot of round duct, surface area in square feet per lineal foot of round duct, rectangular equivalents of round duct sizes, weight per linear foot of rectangular duct and surface area in square feet per linear foot of Rectangular duct. Back of calculator has equivalent feet of straight duct for commonly used fittings, corrected pressure drop chart, and many HVAC formulas. Pull out slide has recommended duct velocities, recommended gauges for sheet metal, and much more. The photo shows front side of the tool. This slide is made of thick durable water resistant paper stock with glued edges and corner rivets. Tool measures 4 inches high and 8.5 inches wide. Picture shows front and back.