CIDR subnet calculator
Paste an IPv4 block in CIDR notation to see the network boundaries, usable host range and how many addresses it covers. Everything is computed in your browser.
Back to toolsNetwork address192.168.1.0
Broadcast address192.168.1.255
First usable host192.168.1.1
Last usable host192.168.1.254
Subnet mask255.255.255.0
Wildcard mask0.0.0.255
Prefix length/24
Total addresses256
Usable hosts254
Why abuse teams care about ranges
Hosting providers and proxy vendors do not buy single addresses — they announce whole prefixes. When one address in a /24 is abusive, its neighbours frequently are too, which is why range ownership and ASN data carry more weight than a single-address reputation hit. Blocking a full prefix is powerful and blunt: check the usable host count here before you commit to it.