How many bits are in an IPv4 address?

An IPv4 address contains 32 bits.

Those 32 binary digits are usually written as four decimal numbers separated by periods, such as 192.0.2.1. Each decimal section represents eight bits, so it can range from 0 through 255. This format is called dotted-decimal notation.

The 32-bit address space contains 2³² possible combinations, or 4,294,967,296 addresses. Some are reserved for private networks, testing, multicast, or other special purposes, so the number available for ordinary public assignment is smaller.

IPv4 became increasingly strained as the Internet expanded. Network address translation helped many devices share one public address, but the long-term solution is IPv6, which uses 128-bit addresses. IPv4 and IPv6 are different protocols, although many networks operate both at the same time.