How many bits are in an IPv4 address?

• A. 8
• B. 16
• C. 32
• D. 64

Answer: (C)

IPv4 addresses are 32 bits long. They’re made up of four octets, each 8 bits, usually written in dotted decimal notation like 192.168.0.1. Because there are four octets and each contributes 8 bits, the total is 4 × 8 = 32 bits. This structure allows 2^32 possible addresses, about 4.29 billion. For contrast, IPv6 uses 128 bits, offering vastly more addresses.