Calculate subnet masks, network addresses, broadcast addresses, and usable host ranges from CIDR IP addresses. Ideal for network planning and management.
Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and IP routing. CIDR notation uses a suffix (e.g., /24) to indicate the number of bits in the network prefix. This calculator helps network engineers determine the subnet mask, network address, broadcast address, and usable IP range for a given CIDR block.
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Random IP Address Generator
Generate IPv4 and IPv6 addresses on demand. Supports specific public/private networks and custom CIDR ranges. Ideal for testing, development, and learning.
IPv4 / IPv6 Address Converter
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Manually calculating subnet addresses during network planning is time-consuming and prone to errors. The CIDR Subnet Calculator quickly parses IPv4 addresses in CIDR format, automatically outputting the network address, broadcast address, subnet mask, and usable host range. CIDR (Classless Inter-Domain Routing) is an IP address allocation method that represents subnets using the "IP address/prefix length" format (e.g., 192.168.1.0/24), where the prefix length defines the number of network bits.
Does the CIDR calculator support IPv6 addresses?
No, the current tool only processes CIDR calculations for IPv4 addresses.
Why is the number of usable hosts 2 less than the total number of hosts?
Because the network address and broadcast address in each subnet cannot be assigned to hosts. For example, a /24 subnet has 256 total addresses, but only 254 usable hosts.
Please ensure the input format is "IPv4 address/prefix length", with a prefix range between 8 and 32. The calculation results are for reference only; actual network deployment should be based on your specific network equipment configurations. This tool does not store the IP addresses you enter, ensuring your privacy is protected.
For a /24 subnet (subnet mask 255.255.255.0), the usable host range is from the network address + 1 to the broadcast address - 1. For example, the usable IPs for 192.168.1.0/24 are 192.168.1.1 to 192.168.1.254. When planning subnets, it is recommended to reserve a 10% address margin to accommodate future expansion needs.
