Why do ceramic capacitors have no polarity?

Ceramic capacitors use a ceramic dielectric (like barium titanate or similar materials), which has symmetric electrical properties. Internally, they are made by stacking alternating layers of metal electrodes and ceramic dielectric material.

Since both electrodes are essentially the same and the dielectric doesn’t rely on an electrochemical process, the capacitor behaves the same regardless of the direction of current or applied voltage. That’s why they don’t require a positive or negative terminal, unlike electrolytic capacitors.

Electrolytic capacitors, on the other hand, rely on an electrolytic solution and a thin oxide layer formed only on the positive plate during manufacturing. Reversing the polarity can damage this oxide layer, hence the need for correct polarity.

It's all about what they're made of inside.

Basically, ceramic capacitors use a ceramic material as the dielectric (the stuff between the metal plates). This material doesn't care which way the electricity flows. you can hook it up forwards, backwards, sideways... it'll still work just fine. It's a "non-polarized" material.

Capacitors that do have polarity, like electrolytic capacitors, are different. They use a super-thin layer of metal oxide that's created through a chemical process. This layer only works as an insulator in one direction. if you hook it up backwards, you destroy that layer, and boom! The capacitor can literally pop or vent.

So yeah, the short answer is:

Ceramic caps use a material that isn't direction-sensitive. Electrolytic caps use a chemically-formed layer that is.

That's why you gotta double-check the little '+' and '-' signs on some caps but can just swap a ceramic one in either way.