🔧 Cv Flow Calculator
Enter liquid flow rate, specific gravity, and pressure drop across a valve to calculate its flow coefficient (Cv).
What is Cv?
The flow coefficient (Cv) of a valve describes how much liquid it can pass for a given pressure drop, letting engineers select and size control valves without needing to test every specific application.
The formula
For liquid flow in US units, Cv = Q × √(SG ÷ ΔP), where Q is flow rate in gallons per minute, SG is the fluid’s specific gravity relative to water, and ΔP is the pressure drop across the valve in psi. Cv is defined as the flow rate of 60°F water (in GPM) that produces a 1 psi pressure drop through the valve.
This formula applies to fully turbulent, non-flashing, non-cavitating liquid flow; compressible gas flow and choked flow conditions require different formulas. This calculator is for general fluid engineering education and preliminary valve sizing reference.