What this calculator does
This tool estimates fluid flow rate through a restriction (like an orifice plate or venturi meter) from the measured pressure difference across it, a common industrial flow measurement technique.
The formula
Flow velocity through the restriction is v = Cd√(2ΔP/ρ), where Cd is the discharge coefficient (accounting for real-world losses, typically around 0.6-0.65 for a sharp-edged orifice), ΔP is the differential pressure, and ρ is the fluid density. Volumetric flow rate is then Q = A × v, where A is the restriction’s flow area.
This is a standard simplified flow measurement formula; precise industrial metering also accounts for pipe geometry (beta ratio), Reynolds number, and expansion factors per relevant flow measurement standards.
Last reviewed August 2026