About IP Subnetting & CIDR
Subnetting is the practice of dividing a network into two or more smaller networks (subnets). Classless Inter-Domain Routing (CIDR) is an IP addressing scheme that improves the allocation of IP addresses. Instead of using traditional Classes A, B, and C, CIDR uses a slash prefix (such as /24) to denote the number of shared network routing bits, allowing much more flexible subnet definitions.
How to use the Subnet Calculator
1. Input IP Address: Enter any valid IPv4 address (e.g., 192.168.1.1 or 10.0.0.100).
2. Adjust CIDR Mask: Use the slider or dropdown select box to adjust the network bits (/0 to /32). The matching dotted subnet mask (e.g. 255.255.255.0) updates instantly.
3. Analyze Binary Bits: Inspect the color-coded binary display at the bottom to visualize the boundary between the Network ID and Host ID.
Key Subnet Terms
- Network Address: The first address in the subnet, used to identify the subnet itself. Cannot be assigned to hosts.
- Broadcast Address: The last address in the subnet, used to send data packets to all hosts in the subnet. Cannot be assigned to hosts.
- Usable Host Range: The range of IP addresses between the Network and Broadcast addresses that can be assigned to devices.
Privacy first: Subnet calculations are calculated 100% locally in your browser. Absolutely zero network traffic is sent to external servers.