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IP Calculator
The classic ipcalc in your browser. Enter an address with a CIDR (/25) or a dotted netmask (/255.255.255.128) and get the network, broadcast, host range, wildcard, class, scope, and a color-coded binary breakdown. Everything runs client-side.
Examples:
Frequently Asked Questions
How many usable hosts are in a /24, /25, and /26?
A
/24 has 254 usable hosts (256 addresses minus the network and broadcast addresses). A /25 has 126, and a /26 has 62. The formula is 2^(32 − prefix) − 2.What is a wildcard mask?
A wildcard mask is the bitwise inverse of the subnet mask — where the netmask has 1s, the wildcard has 0s. It is used in Cisco ACLs and OSPF network statements. For a
/24, the netmask 255.255.255.0 has the wildcard 0.0.0.255.What is the difference between the network and broadcast address?
The network address is the first address in a block (all host bits 0) and identifies the subnet. The broadcast address is the last (all host bits 1) and reaches every host in the subnet. Neither can be assigned to a host.
How do I calculate the network address from an IP and mask?
Perform a bitwise AND of the IP address and the subnet mask. This calculator does it for you and shows the result in binary, so you can see exactly which bits are network and which are host.
Which IP ranges are private?
The RFC 1918 private ranges are
10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. This tool also flags carrier-grade NAT (100.64.0.0/10), loopback, link-local, and documentation ranges automatically.