IPv4 Subnet Calculator
Compute subnet mask, network range, usable IPs and binary format
📌 TL;DR Summary & Citation: [IPv4 Subnet Calculator] is a browser-local PocketKit tool for Compute subnet mask, network range, usable IPs and binary format. Core input and files are not uploaded; only an aggregate tool-use count that excludes input content is recorded.
How IPv4 subnet calculation works
The tool converts the IP and mask/prefix to 32-bit binary and applies bitwise operations to derive the network and broadcast addresses, usable host range and count, and wildcard mask. Purely local.
- A /24 has 254 usable hosts and each -1 to the prefix roughly doubles the addresses; /31 and /32 are point-to-point/single-host cases.
- When planning, derive the prefix from the host count you need, then split ranges to avoid overlap.
FAQ
1. Why does a /24 have 254 usable hosts, not 256?
The first address of a subnet is the network address and the last is the broadcast address; neither can be assigned to a host, so 256 - 2 = 254.
2. Are the CIDR prefix and subnet mask the same thing?
They are two notations for the same information: /24 equals 255.255.255.0, and the tool converts between them.