Enter your Electric Field Strength (E) and choose your preferred Electric Field Unit to calculate the Electrostatic Pressure acting on a charged surface — your results appear as Pressure in kPa and Force per Unit Area in whatever Pressure Output Unit you select.
Electrostatic Pressure
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Pressure in kPa
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Force per Unit Area
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Electrostatic pressure is the force per unit area exerted on a charged surface in the presence of an electric field. It represents the mechanical stress experienced by the surface due to electrostatic forces.
The electrostatic pressure formula is P = ½ε₀E², where P is the pressure, ε₀ is the electric constant (8.854 × 10⁻¹² F/m), and E is the electric field strength.
The calculator accepts electric field values in V/m (volts per meter), N/C (newtons per coulomb), or kV/m (kilovolts per meter). All units are equivalent as 1 V/m = 1 N/C.
The factor of ½ comes from the fact that electrostatic pressure is the average of the discontinuous electric field at the surface charge. It represents the mean value of the field just inside and outside the charged surface.
Electrostatic pressures are generally very small. For example, an electric field of 100 kV/m produces a pressure of only about 0.044 Pa, which is much smaller than atmospheric pressure (101,325 Pa).
Electrostatic pressure is important in capacitor design, electrostatic precipitators, Van de Graaff generators, lightning rods, and any application involving high electric fields near charged surfaces.
Electrostatic pressure increases with the square of the electric field strength. Doubling the electric field results in four times the pressure, making high-field applications particularly sensitive to field variations.
The electric constant (ε₀) is the permittivity of free space, with a value of approximately 8.854 × 10⁻¹² F/m (farads per meter). It's a fundamental physical constant in electromagnetism.