Do I Need a Power Converter?

It will depend on where you are from.
US Teachers usually have no trouble.

Voltage wise, universally in the world most of the laptops and small electronics and chargers are able to handle anywhere from 110 to 220V. (China is 220V). You can check the cord or box and it will usually read something like 100-240 (or 110-220)

Size for fitting into the electrical socket:
The standard two flat prong charger plugs work perfectly.
For Canadians if you have the third ground prong on your plug, then you normally need an extension piece to make it 2 prongs instead of the three.
The UK plug generally needs the adapter.

All hair dryers usually don’t convert. Those usually cannot handle the different voltages and you can buy another one inexpensively in China.