IP Subnet Calculator
CIDR & Host Range
Calculate IPv4 CIDR network address, subnet mask, wildcard mask, broadcast address, host range, and usable hosts.
What is this tool?
This IPv4 subnet calculator derives network information from an address and CIDR prefix. It calculates the network address, subnet mask, wildcard mask, broadcast address, first host, last host, and usable host count.
CIDR notation expresses how many leading bits belong to the network. For example, /24 leaves 8 host bits and creates a 256-address block, while /30 leaves only 2 host bits and is often used for tiny point-to-point ranges.
Use this tool before changing firewall rules, VPN routes, cloud VPC settings, router ACLs, or documentation where an off-by-one address range can break connectivity.
How to use
- Enter an IPv4 address such as
192.168.1.10. - Enter a CIDR prefix from
0to32. - Click Calculate to derive network details.
- Copy the summary into a ticket, firewall change, runbook, or network plan.
Examples
| Input / setting | Output | Notes |
|---|---|---|
192.168.1.10 /24 | network 192.168.1.0; mask 255.255.255.0; broadcast 192.168.1.255; hosts 192.168.1.1-192.168.1.254; usable 254 | A common private subnet. |
10.0.0.5 /30 | network 10.0.0.4; mask 255.255.255.252; broadcast 10.0.0.7; hosts 10.0.0.5-10.0.0.6; usable 2 | A small point-to-point style range. |
Related tools & concepts
Last reviewed: 2026-05-08