IPv4 Subnet Calculator

Calculate network details from an IP address and subnet mask. Understand your network structure, available hosts, and address ranges instantly.

Input

IP Address Enter any valid IPv4 address (e.g., 10.0.0.1)

Subnet Mask or CIDR

CIDR Prefix Range: /0 to /32 (common: /8, /16, /24, /30)

Subnet Mask e.g., 255.255.255.0 or 255.255.0.0

Enter an IP address and subnet to see the results

This subnet calculator helps you understand IPv4 network structure and addressing:

IP Address: Enter any IPv4 address from your network (e.g., 192.168.1.100)
CIDR Notation: Use /24, /16, etc. Common values: /8 (16M hosts), /16 (65K hosts), /24 (254 hosts), /30 (2 hosts)
Subnet Mask: Alternative to CIDR, like 255.255.255.0 for /24

Network Address: The first address in the subnet (not usable for hosts)
Broadcast Address: The last address in the subnet (used to send to all hosts)
First/Last Usable Host: The range of IPs you can assign to devices
Total Hosts: All addresses in the subnet, including network and broadcast
Usable Hosts: Addresses available for devices (Total - 2)

/8 = 16,777,216 hosts (Class A) •/16 = 65,536 hosts (Class B) •/24 = 256 hosts (Class C) •/30 = 4 hosts (point-to-point links)