Bernoulli Equation Calculator
Enter the fluid density, the conditions at point 1 and the velocity and height at point 2. The calculator solves Bernoulli's equation for the pressure at point 2.
How to use Bernoulli's equation
- Enter the fluid density in kg/m3.
- Enter the pressure, velocity and height at point 1.
- Enter the velocity and height at point 2.
- Read the solved static pressure at point 2.
Examples
Speed up, same height
rho 1000, P1 200000, v1 2, v2 5, equal heights
P2 = 189500 Pa
Drop 2 m, same speed
rho 1000, P1 200000, equal speeds, h2 = -2 m
P2 = 219613.3 Pa
Frequently asked questions
What is Bernoulli's equation?
P + half rho v squared + rho g h is constant along a streamline. Rearranged, P2 = P1 + half rho times (v1 squared minus v2 squared) plus rho g times (h1 minus h2).
What assumptions does it make?
It assumes steady, incompressible, frictionless flow along a single streamline with no energy added or removed by pumps or turbines.
Why does pressure fall when the fluid speeds up?
Total energy is conserved, so a larger velocity term means a smaller pressure term. Faster flow at the same height has lower static pressure.
What sign should I use for height?
Heights are elevations on any consistent axis. A point that sits lower than point 1 has a smaller or negative height value.
What value of gravity is used?
The calculator uses standard gravity, g = 9.80665 m/s squared, in the elevation term rho g times the change in height.
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