Subnet Calculator
Calculate network addresses, subnet masks, and IP ranges for your network
Common Subnets
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What is Subnetting?
Subnetting is the practice of dividing a network into smaller networks called subnets. It helps organize networks efficiently, improve security, and optimize network performance. Each subnet can be treated as a separate network with its own range of IP addresses.
CIDR Notation
CIDR (Classless Inter-Domain Routing) notation represents subnet masks in a compact format. For example, /24 means the first 24 bits are the network portion, leaving 8 bits for hosts (256 addresses). Common notations: /24 = 255.255.255.0 (254 usable hosts), /16 = 255.255.0.0 (65,534 usable hosts).
Private IP Ranges
Private IP addresses are reserved for internal networks and not routable on the public internet. The private ranges are: Class A (10.0.0.0/8), Class B (172.16.0.0/12), and Class C (192.168.0.0/16). These addresses can be used freely within private networks.
Usable vs Total Addresses
The total number of addresses in a subnet includes the network address and broadcast address, which cannot be assigned to hosts. Therefore, usable addresses = total addresses - 2. For example, a /24 network has 256 total addresses but only 254 usable for devices.