Overview

Calculate network address, broadcast address, usable host range, and CIDR notation based on an IP address and subnet mask. An essential tool for network design and subnetting.

Formula

Subnet calculation: Network address = IP AND subnet mask. Broadcast address = IP OR (NOT subnet mask). Usable hosts = 2^(32−CIDR) − 2 (excluding network and broadcast addresses). First host = network address + 1. Last host = broadcast address − 1. Example: 192.168.1.100/24 → subnet mask 255.255.255.0, network 192.168.1.0, broadcast 192.168.1.255, host range 192.168.1.1–254, 254 usable hosts.

How to Use

1. 1Enter an IP address (e.g., 192.168.1.100).
2. 2Enter a subnet mask or CIDR prefix length (e.g., 255.255.255.0 or /24).
3. 3Review the calculated network information.
4. 4Use the subnetting option if subnet division is needed.

Tips

• ✔CIDR notation (/24) indicates the number of leading bits in the subnet mask. /24 = 255.255.255.0.
• ✔Private IP ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16.
• ✔/31 represents 2 hosts (point-to-point), and /32 represents a single host.
• ✔Using VLSM (Variable Length Subnet Masking) allows more efficient IP address allocation.

FAQ