Convert an IPv4 address between dotted-decimal and binary notation.
Each IPv4 address is a 32-bit number, conventionally written as four decimal octets (0–255) separated by dots. Converting to binary means expressing each octet as its 8-bit binary equivalent — for example 192 becomes 11000000 — and concatenating all four to get the full 32-bit binary form of the address.
Octet to binary
Each decimal octet (0–255) maps to an 8-bit binary value
An octet's decimal range is 0–255, and 8 bits can represent exactly 256 values (0 to 255), so 8 bits per octet is the natural fit for a 32-bit address split into four parts.
255 in binary is 11111111 — all eight bits set to 1, which is why it's used in subnet masks.
Subnetting decisions (which bits are network vs. host bits) are made by looking at the binary form of the address and mask side by side, which is exactly what this converter shows.