Core transformations run locally in your browser.
Calculate network addresses, subnet masks, wildcard masks, broadcast addresses, and host ranges from an IPv4 CIDR block. All calculations run locally.
IPv4 only. /31 uses point-to-point host rules; /32 identifies one address. Usable counts are mathematical, not a guarantee that every address can be assigned in your network or cloud provider.
Enter an IPv4 address followed by a prefix, such as 192.168.1.10/24. A /24 subnet contains 256 addresses; under ordinary subnet rules, 254 are host addresses. The calculator normalizes your host address to its network boundary and shows the full range.
A /31 provides two addresses for point-to-point links under RFC 3021, without a directed broadcast address. A /32 represents a single host address. Larger subnets reserve the first and last addresses for the network and broadcast. Cloud providers can reserve additional addresses, so these mathematical counts are not provider allocation limits.
The prefix counts network bits in the 32-bit IPv4 address. A /24 corresponds to 255.255.255.0; the inverse wildcard mask is 0.0.0.255. This tool supports IPv4 only and does not perform network scans or check whether an address is reachable.