Calculate IPv4 subnet details
Enter an IPv4 address and CIDR prefix. The calculator will show the main subnet details used for networking, routing, firewall rules, documentation, and troubleshooting.
Subnet result
Enter an IP address and prefix.
Tech Tool
IPv4 Subnet Calculator
Calculate subnet mask, wildcard mask, network address, broadcast address, first usable host, last usable host, total addresses, and usable host count from an IPv4 address and CIDR prefix.
About this IPv4 subnet calculator
This IPv4 subnet calculator helps calculate common subnet values from an IPv4 address and CIDR prefix. It is useful for network administrators, students, home lab users, IT support work, firewall planning, and technical documentation.
CIDR prefix
CIDR notation uses a slash followed by a number, such as /24. The number shows how many bits are used for the network portion of the address.
Subnet mask
The subnet mask separates the network portion of an IPv4 address from the host portion. It is commonly written as four decimal octets.
Usable host range
For most traditional IPv4 subnets, the first address is the network address and the last address is the broadcast address. The usable hosts are usually between those two values.
Subnet calculation notes
This tool calculates standard IPv4 subnet information for common planning and troubleshooting. A /31 network is often used for point-to-point links, and a /32 represents a single host route. Some environments may handle those ranges differently depending on routing, firewall, or platform behavior.
Network address
The network address identifies the subnet itself. It is calculated by applying the subnet mask to the IPv4 address.
Broadcast address
The broadcast address is the last address in the subnet for traditional IPv4 networks.
Wildcard mask
A wildcard mask is the inverse of the subnet mask. It is often used in access control lists and some routing configurations.
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