Dynamic Pressure (q = ½ρv²)

q = \tfrac{1}{2} \rho v^{2}

q =

ρ =

v =

Enter your known values, leave one input blank, and solves for the missing one. Try different units for next level excitement!

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Dynamic pressure is $\tfrac{1}{2}mv^2$ written per unit volume, and it is what a moving fluid can push with when brought to rest. An aircraft's pitot tube measures exactly this — the difference between ram pressure facing the flow and static pressure beside it — and converts it back to airspeed via $v = \sqrt{2q/\rho}$ . A 30 m/s wind (about 108 km/h) carries $q = \tfrac{1}{2} \times 1.225 \times 30^2 \approx 551\ \text{Pa}$ , over half a kilonewton on every square meter of a billboard.

Dynamic Pressure (q = ½ρv²)

q = \tfrac{1}{2} \rho v^{2}

Where

$q$ = Dynamic pressure
$\rho$ = Fluid density
$v$ = Flow velocity

Missing one of these? Work it out first, then come back

Dynamic pressure — Pressure Head (h = P/ρg), Poiseuille's Law
Fluid density — Buoyant Force (Archimedes' Principle), Pressure Head (h = P/ρg)
Flow velocity — Volumetric Flow Rate (Q = Av), Velocity Head (h = v²/2g)

Part of this formula set

Duct sizing and airflow

5 formulasDuct velocity, equivalent round diameter, velocity pressure and air changes per hour — sizing ductwork and proving the room turns over.