What is the difference between symmetric and asymmetric key sizes?

Symmetric key sizes are fixed lengths and are usually around 128, 192, or 256 bits. Asymmetric key sizes, on the other hand, can range from 512 bits to around 4,096 bits. Asymmetric keys are also known as Public Key Cryptography, which is more secure than symmetric keys. Asymmetric keys require more computing power to generate and manipulate, which makes them more secure.