Capacitance Calculator

A smaller gap means the electric field between the plates is stronger for the same applied voltage, which lets the plates hold more charge before that voltage limit is reached. Since capacitance is defined as charge per volt, a stronger field per volt of separation directly increases capacitance -- this is why real capacitors use very thin dielectric layers to pack more capacitance into a small physical size.

It measures how much an insulating material between the plates amplifies capacitance compared to a vacuum gap of the same size. A dielectric material's molecules polarize in the electric field, partially canceling it and letting the plates store more charge at the same voltage -- vacuum and air sit at essentially 1, while materials like glass or ceramic can reach into the hundreds or thousands for specialty capacitor dielectrics.

In the idealized model used here, yes -- the field is treated as uniform between infinite parallel plates, giving the simple E = V/d relationship. Real, finite-sized plates have some field bulging (fringing) near their edges that this calculator does not model, which makes the idealized formula most accurate when the plate separation is small compared to the plates' width and length.

Both electric field and charge scale linearly with applied voltage in this model, so multiply the calculator's reported Electric Field at 1 V or the underlying charge figure by your actual voltage to get the real value. For example, at 12 volts the field and charge are both 12 times the calculator's 1-volt reference values.