FLOW COEFFICIENT · ISA / IEC 60534
Valve Pressure Drop (ΔP) Calculator
Calculate the pressure drop across a control or isolation valve from its flow coefficient (Cv or Kv), or work backwards to find the flow a valve will pass at a given differential pressure — for liquids, gases and steam.
Liquid Gas Steam
Solve for
Pressure drop (ΔP) Flow rate
Equation used
Engineering note: Results use the standard ISA / IEC 60534 sizing relationships and are for guidance only. They assume turbulent, non-choked flow and a fully-open valve unless a Cv for the actual opening is entered. Always confirm against the manufacturer's published Cv/Kv, and check for choked flow, cavitation and flashing at high pressure drops.
Cv vs Kv: Cv is in US gpm at 1 psi drop (60 °F water); Kv is in m³/h at 1 bar drop (water). Kv = 0.865 × Cv. Pick the coefficient that matches your valve data sheet.
