IPv4 Subnet Calculator

What it does

Enter an IPv4 address with a CIDR prefix (e.g. 192.168.1.10/24) and get:

• Network address
• Broadcast address
• Usable host range
• Number of usable hosts
• Subnet mask and wildcard mask

Try it

How it works

1. The IP is parsed into 4 octets and converted to a 32-bit integer.
2. The subnet mask is derived from the CIDR prefix length (/0 to /32).
3. Network address = IP AND mask.
4. Broadcast address = Network address OR (NOT mask).
5. Usable hosts = network address and broadcast address are excluded (except for /31 and /32, which are handled as special cases per RFC 3021).

All math happens in your browser — nothing is sent anywhere.