Enter an IPv4 address and CIDR prefix to get the full subnet breakdown instantly.
This tool provides subnet calculations for informational and educational purposes only. Always verify network configurations with a qualified network engineer before deployment in production environments.
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Subnetting is the process of dividing a larger IP network into smaller, more manageable sub-networks (subnets). This IP subnet calculator takes any IPv4 address and CIDR prefix length and instantly tells you the network address, subnet mask, wildcard mask, broadcast address, first and last usable host addresses, and the total number of hosts. Whether you are studying for CompTIA Network+, CCNA, or simply setting up a home or business network, this tool handles the binary arithmetic for you.
CIDR (Classless Inter-Domain Routing) notation writes an IP address followed by a slash and the prefix length — for example, 192.168.1.0/24. The number after the slash tells you how many bits are used for the network portion of the address. The remaining bits are available for host addresses.
For a /24 network with IP 192.168.10.50:
From a /24, you can borrow bits from the host portion. Borrowing 1 bit gives /25 (2 subnets × 126 hosts). Borrowing 2 bits gives /26 (4 subnets × 62 hosts). Each additional bit doubles the subnets and halves the hosts.
The subnet mask identifies network bits with 1s and host bits with 0s. The wildcard mask is the inverse — it identifies host bits with 1s. For /24: mask = 255.255.255.0, wildcard = 0.0.0.255.
The first address is the network address (identifies the subnet). The last address is the broadcast address (reaches all hosts). Both are reserved and cannot be assigned to devices.