Parallel-Plate Capacitor Calculator

This calculator finds the capacitance of a parallel-plate capacitor from the area of its plates, the gap between them, and the dielectric material in between. A capacitor stores electrical energy by holding charge on two conducting plates separated by an insulator, and the parallel-plate design is the simplest and most instructive form. Its capacitance, the amount of charge it stores per volt applied, depends on three things in a beautifully direct way: it grows with the area of the plates, shrinks as the gap between them widens, and increases with the dielectric constant of the insulating material between them. This relationship is the foundation for understanding all capacitors, and it explains the design choices in everything from electronic components to touchscreens and sensors. This calculator computes it. You enter the plate area in square metres, the separation between the plates in metres, and the relative permittivity, or dielectric constant, of the material in the gap, which is one for a vacuum or air and higher for materials like plastic, glass or ceramic, and the calculator returns the capacitance in farads, picofarads and nanofarads, the usual practical units. The results update as you type. Use it for electronics and physics study, for designing or understanding capacitors, or to see how the plate geometry and dielectric set the capacitance. The capacitance is the permittivity of free space times the dielectric constant times the plate area, divided by the gap. Because capacitance is inversely proportional to the gap, bringing the plates closer together raises it sharply, while a larger area or a higher dielectric constant also increases it, which is why real capacitors use large plate areas rolled up tightly with thin, high-permittivity dielectrics to pack a lot of capacitance into a small component. The permittivity of free space used is about 8.854 times ten to the minus twelve farads per metre.

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C = ε0 x dielectric constant x area / gap, with ε0 = 8.854 x 10^-12 F/m. Capacitance rises with area and dielectric, falls with gap. Dielectric is 1 for air/vacuum.