IPv4 addresses are 32-bit numerical addresses (e.g., 192.168.1.1), capable of providing about 4.3 billion unique addresses. IPv6 addresses are 128-bit hexadecimal addresses (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334), designed to accommodate the growing number of internet-connected devices with a much larger address space.