Balou Tools

Subnet Calculator

Calculates IP networks, CIDR masks, host ranges, and broadcast addresses.

Guide & best practices

Subnet Calculator for CIDR, hosts and wildcard masks

Plan IP ranges reliably: from IP and prefix Balou derives network, broadcast, usable hosts and mask for network design and ACLs.

Typical use cases

Useful for network planning, VLAN/subnet design, firewall and ACL rules, cloud VPC layouts and quickly checking CIDR ranges.

How the subnet calculator works

Enter an IP address and CIDR prefix or mask; Balou computes the network, broadcast and host range, host count and wildcard mask locally.

Subnet planning best practices

Plan prefixes with headroom, document subnet boundaries, use /64 as the default LAN prefix for IPv6 and check for overlaps before routing.

Frequently asked questions

What does /24 (CIDR) mean?

A /24 equals the mask 255.255.255.0 with 256 addresses and 254 usable hosts (network and broadcast address excluded).

How do I compute network and broadcast address?

Example 192.168.10.37/27: network 192.168.10.32, broadcast 192.168.10.63, usable hosts 192.168.10.33–.62.

What is a wildcard mask?

The inverted subnet mask (e.g. 0.0.0.255 for /24), often used in router/firewall ACLs.

How do IPv4 and IPv6 subnets differ?

IPv6 uses much larger prefixes; /64 is the common default LAN prefix for a single segment.