AUTHAvailable
Valve Authority Calculator
CalculatorCalculate valve authority from fully open valve and remaining circuit pressure drops.
Open calculatorEngineering tools
Valve Cv Calculator
Calculate liquid valve Cv from flow, valve pressure drop, and specific gravity.
Quick start
Enter liquid flow, pressure drop across the valve and specific gravity, then select Calculate. Choose units beside the inputs. The result is a required flow coefficient; valve size and product selection need separate review.
Inputs
Result
Enable JavaScript to calculate.
Method & assumptions
Cv = Q(US gpm) × √(SG / ΔP(psi))
For non-choked turbulent liquid flow. The calculator converts the entered units to US gpm and psi before calculating Cv. Flow, pressure drop, and specific gravity must be positive. Water uses SG = 1 as an approximation.
Reference: Swagelok · Valve Sizing · Methods, conversion conventions, and source notes
Worked example
10 US gpm at a 4 psi valve pressure drop with SG = 1 gives Cv = 5.
Frequently asked questions
Does Cv specify a valve size?
No. Cv is a flow coefficient. Valve type, size, characteristic, operating conditions, and actuator requirements need separate review.
Recommended parts
Product recommendations have not been added. Calculated values are not product endorsements.
About recommended parts