IPv4 Subnet Calculator
Calculate network address and host range for any CIDR.
How to Use
- Enter an address in CIDR notation (e.g. 192.168.1.0/24) or an IP address with a subnet mask.
- The tool calculates and displays: network address, broadcast address, subnet mask, usable host range, and the number of available hosts.
- Copy the calculated results you need for your network configuration.
Frequently Asked Questions
- What is CIDR notation?
- CIDR (Classless Inter-Domain Routing) notation represents an IP address and its associated network prefix length. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for host addresses — allowing 254 usable hosts.
- How do I calculate the number of usable hosts?
- Usable hosts = 2^(host bits) - 2. Subtract 2 because the first address is the network address and the last is the broadcast address. For a /24 network: 2^8 - 2 = 254 usable hosts.
- What is the subnet mask for /24?
- A /24 prefix means 24 bits are set to 1 in the subnet mask, resulting in 255.255.255.0. Similarly, /16 = 255.255.0.0 and /8 = 255.0.0.0. The subnet mask defines which part of the IP address identifies the network.