IP Subnet Calculator
Calculate IPv4 CIDR details such as netmask, broadcast address, host range, and usable host count instantly.
This tool runs entirely in your browser. Your input is never uploaded.
Invalid IPv4 address format.
IP Subnet Calculator
Planning VLANs, firewall rules, or DHCP scopes gets easier when you can see the full picture of a subnet. Enter any IPv4 address with a prefix length — from /0 up to /32 — and this calculator derives the network address, broadcast address, netmask, wildcard mask, first and last usable hosts, and total capacity using pure bit arithmetic.
Edge cases follow current practice: /31 links get two usable addresses per RFC 3021, and /32 host routes count as their own usable address. Binary representations of the network and mask help when studying for networking certifications or verifying ACL wildcards.