How it works
Calculate IPv4 subnet details from an address and CIDR prefix length.
Enter an IPv4 address and a prefix length (0–32). The calculator derives the network and broadcast addresses, usable host range, subnet and wildcard masks, and address counts.
Formula
network = ip AND mask; broadcast = network OR wildcard; total = 2^(32 − prefix).
ip- IPv4 address
prefix- CIDR prefix length (0–32)
mask- Subnet mask
Examples
- 192.168.1.37/24IP 192.168.1.37 · prefix 24Network 192.168.1.0 · broadcast 192.168.1.255 · 254 usable hosts
Frequently asked questions
What are usable hosts?
For prefixes 0–30, the network and broadcast addresses are reserved, leaving 2^(32 − prefix) − 2 usable hosts. /31 (point-to-point) has 2 and /32 has 1.
Does this support IPv6?
No — this calculator handles IPv4 only.
How to read the result
The result shows the full address space of the subnet, which is useful for planning and configuration.
Limitations
IPv4 classless (CIDR) addressing only.
Source: Standard IPv4 CIDR bit-mask arithmetic (RFC 4632).