Young-Laplace Equation Calculator

Your details

Select the shape of the interface. Spherical: droplet or bubble with one radius. Cylindrical: long jet or fiber. General: ellipsoidal or saddle-shaped surface with two radii. Capillary: rise height in a tube.
Preset fills in surface tension and density automatically. Choose Custom to enter your own values.
Sphere/cylinder: the single radius. General mode: first principal radius R1.
mm
Pressure difference (dP)
145.6Pa

The Young-Laplace pressure jump across the interface (pascals)

Pressure difference0.1456kPa
Pressure difference0.00143696atm
Formula applieddP = 2*gamma / R (spherical)
Pressure difference (Pa)145.6

Capillary pressure difference: 145.60 Pa

  • A spherical droplet (or bubble) of water with radius 1 mm has an internal excess pressure of 145.60 Pa relative to the surrounding fluid.
  • Smaller droplets have higher internal pressure. Halving the radius doubles the pressure difference.
  • At 145.60 Pa, this pressure is 0.1437% of one atmosphere.

Next stepSwitch to Capillary rise mode to calculate the equilibrium height in a tube, or try different radii to explore the curvature-pressure relationship.

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