IPv4 Subnet Calculator
Enter an IP address and CIDR prefix to calculate the network address, broadcast address, host range, and subnet size.
About this tool
IPv4 Subnet Calculator takes an address and a CIDR prefix (like /24) or subnet mask and works out everything that subnet implies: the network address (the subnet's identifier), the broadcast address (used to reach every device on the subnet at once), the range of host addresses actually assignable to devices, and how many total and usable addresses the subnet contains.
A /24 is the classic "256 addresses, 254 usable hosts" home/office network size; smaller prefixes (like /16) cover far more addresses, while larger ones (like /30, with just 2 usable hosts) are typically used for point-to-point links between two routers. For /31 and /32 networks — special cases with no usable host range in the traditional sense — the tool still shows the full address range.
Version 1.0.0