IPv4 Subnet Calculator
Calculate IPv4 subnet information from CIDR notation. Free online subnet calculator showing network address, broadcast, usable hosts, and mask.
What is IPv4 Subnet Calculator?
An IPv4 subnet calculator takes a CIDR notation (like 192.168.1.0/24) and calculates all subnet properties: network address, broadcast address, subnet mask, usable host range, and total hosts. This is essential for network planning, firewall configuration, and understanding IP address allocation.
How to Use
- Enter an IP address with CIDR notation (e.g., 192.168.1.0/24)
- Click Calculate or press Enter
- Results show: network address, broadcast, subnet mask, host range, and more
- IP class and type (Public/Private) are detected automatically
Examples
Class C /24 subnet
Small /28 subnet
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Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation specifies a subnet using an IP address followed by / and the number of network bits. For example, /24 means the first 24 bits are the network portion, leaving 8 bits for hosts (256 addresses).
What's the difference between total and usable hosts?
Total hosts includes all addresses in the subnet. Usable hosts excludes the network address (first) and broadcast address (last). For a /24 subnet: 256 total - 2 = 254 usable.
What are private IP ranges?
10.0.0.0/8 (Class A), 172.16.0.0/12 (Class B), and 192.168.0.0/16 (Class C). These addresses are not routable on the public internet and are used for internal networks.