A duct size calculator, commonly known as a ductulator, depends on factors like the size of the space you’re heating or cooling, air flow velocity, friction loss, and available static pressure of the HVAC system.
Air Duct Components - Minor Dynamic Loss Coefficients Component or FittingMinor Loss Coefficient -ξ - 90o bend, sharp 1.3 90o bend, with vanes 0.7 90o bend, rounded radius/diameter duct <1 0.5 90o bend, rounded radius/diameter duct >1 0.25 45o bend, sharp 0.5 45o bend, rounded radius...