IP Subnet Calculator
Calculate subnet details from any IPv4 CIDR address. Get network address, broadcast, host range, subnet mask, wildcard mask, and binary representations.
What Is an IP Subnet Calculator?
An IP subnet calculator takes an IPv4 address and a CIDR prefix length (e.g. 192.168.1.0/24) and computes all key network properties: the network address, broadcast address, usable host range, subnet mask, wildcard mask, and total host count.
How to Use
- Enter an IPv4 address with CIDR notation, e.g.
192.168.1.100/24 - Or enter the IP and adjust the CIDR slider separately
- All subnet details appear instantly
- Click Copy next to any field to copy its value
Features
- Network address, broadcast address, first and last usable host
- Subnet mask and wildcard mask
- Total hosts and usable hosts count
- IP class detection (A, B, C, D)
- Binary representation of IP, mask, and network address
FAQ
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation appends the prefix length to an IP address after a slash: 10.0.0.0/8. The prefix length indicates how many bits of the address are the network part.
Why are /31 and /32 subnets special?
A /32 is a single host (no network/broadcast distinction). A /31 (RFC 3021) is a point-to-point link with 2 usable addresses. This tool reports both addresses as usable for /31 and /32.
What is the wildcard mask used for?
The wildcard mask is the bitwise inverse of the subnet mask. It is commonly used in Cisco ACLs and OSPF configurations to specify which bits of an address must match.
Does this support IPv6?
Currently IPv4 only. IPv6 uses 128-bit addresses which require different calculation logic.