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Venturi Flow Calculator — Differential Pressure to Flow
Calculate ideal incompressible Venturi flow and velocity from inlet/throat diameters, differential pressure, density and discharge coefficient.
Last updated: September 17, 2026
Results
Require D1>D2>0, positive density and a valid Cd
Formula, example and assumptions
Q=Cd·A2·sqrt(2ΔP/[ρ(1−β⁴)]), β=D2/D1.
A 100 mm pipe with 50 mm throat, ΔP=10 kPa, water and Cd=0.98 gives about 0.00355 m³/s.
- Steady incompressible flow and compatible pressure taps are assumed.
- Cd should represent the actual meter and Reynolds-number regime.
Frequently asked questions
What does this Venturi Flow Calculator solve?
Calculate ideal incompressible Venturi flow and velocity from inlet/throat diameters, differential pressure, density and discharge coefficient.
Which units should I use?
Use the SI units shown beside each input. The results also expose practical converted outputs where useful.
Can I use this for final equipment selection?
Use it for transparent engineering estimates and cross-checks. Confirm fluid properties, manufacturer curves and applicable design codes before final selection.