IP Address to Binary
Binary
11000000.10101000.00000001.00000001
How it works
Every IPv4 address is a 32-bit binary number, conventionally displayed as four decimal octets (dotted-decimal notation) for human readability. Converting to binary is essential for understanding subnetting, bitwise masking operations, and how routing tables perform longest-prefix matching.
**The conversion process** Each octet (0–255) converts independently to 8 binary bits. Divide repeatedly by 2, reading remainders from bottom to top — or use the direct bit-weight method: 128, 64, 32, 16, 8, 4, 2, 1. Example: 192 = 128+64 = 11000000. 168 = 128+32+8 = 10101000. 10 = 8+2 = 00001010. 1 = 00000001. Full address: 192.168.10.1 = 11000000.10101000.00001010.00000001.
**Why binary matters for subnetting** The subnet mask operation is a bitwise AND in binary. To find the network address of 192.168.10.130 in a /25 subnet: IP = 11000000.10101000.00001010.10000010, mask = 11111111.11111111.11111111.10000000. AND: 11000000.10101000.00001010.10000000 = 192.168.10.128. That host is in the 192.168.10.128/25 subnet, not the 192.168.10.0/25 subnet.
**IPv6 binary** IPv6 addresses are 128-bit, written as 8 groups of 4 hex digits. Each hex digit is 4 binary bits. 2001:0db8::1 expands to 128 bits. Binary representation is less common in practice for IPv6 (hex is preferred) but the same bitwise prefix-matching logic applies to IPv6 routing.
Frequently Asked Questions
- Convert each of the four octets independently to 8 binary bits using bit weights 128, 64, 32, 16, 8, 4, 2, 1: 192 = 128+64 = 11000000. 168 = 128+32+8 = 10101000. 1 = 00000001. 1 = 00000001. Result: 11000000.10101000.00000001.00000001. Quick check: each octet must produce exactly 8 bits (pad with leading zeros if needed — e.g., 10 = 00001010, not 1010).
- The subnet mask operation is a bitwise AND, which is a binary operation. To determine which subnet a host belongs to: AND the IP address with the subnet mask bit-by-bit. 1 AND 1 = 1, anything AND 0 = 0. Result is the network address. This operation cannot be done correctly without understanding the binary representation — the decimal dotted notation hides the bit structure.
- When all host bits (bits not covered by the subnet prefix) are set to 1, the address is the subnet broadcast address. Packets sent to the broadcast address are delivered to all hosts on that subnet. For 192.168.1.0/24, the broadcast is 192.168.1.255 (00000000 → 11111111 in the last octet). This address cannot be assigned to a host interface.
- IPv6 addresses are 128-bit, written as 8 groups of 4 hex digits. Each hex digit represents 4 binary bits (0=0000, F=1111). The same bitwise AND operation determines the network prefix: IPv6 address AND prefix mask = network address. For a /64 prefix, the first 64 bits are fixed (network); the last 64 bits are the interface identifier (often derived from the MAC address via EUI-64 or randomly generated for privacy).