What is IPv4 Subnet Calculator Online?
IPv4 subnetting divides a large network into smaller, more manageable subnetworks. CIDR notation (e.g., 192.168.1.0/24) expresses both the network address and the subnet mask in a compact format. This calculator breaks down any CIDR block into its network address, broadcast address, first/last usable host, subnet mask, and total number of hosts.
How to Use IPv4 Subnet Calculator Online
- Enter an IPv4 address with CIDR prefix (e.g., 192.168.1.0/24).
- The calculator shows network address, broadcast, host range, and mask.
- Use the results for firewall rules, DNS zones, or network diagrams.
Example
Class A private network
Input
10.0.0.0/8Output
Network: 10.0.0.0 | Broadcast: 10.255.255.255 | Hosts: 16,777,214Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation uses a / prefix length to define a network. /24 means 24 bits for the network, leaving 8 bits for hosts (256 addresses, 254 usable).
What are the private IPv4 ranges?
10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are reserved for private networks (RFC 1918) and are not routable on the public internet.