Free IPv4 subnet calculator: enter an IP and CIDR prefix or subnet mask to get network, broadcast, host range, and wildcard mask instantly. No sign-up.
Added Jun 1, 2026
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Enter a value for ip address to see your result.
Calculates IPv4 subnet details from an IP address and CIDR prefix or subnet mask. Returns network and broadcast addresses, usable host range, host count, wildcard mask, and dotted-binary representation — essential for network design, firewall rules, and cloud VPC planning.
Network = IP AND Mask · Broadcast = Network OR Wildcard
A /24 on 192.168.1.x yields 254 usable hosts — the classic home router subnet.
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A /26 splits a /24 into four subnets of 62 hosts each — common for office VLANs.
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CIDR (Classless Inter-Domain Routing) writes a subnet as an IP address followed by a slash and prefix length — e.g. 192.168.1.0/24. The prefix (24) means the first 24 bits are the network portion; the remaining 8 bits are available for hosts.
A wildcard mask is the bitwise inverse of the subnet mask. It is used in Cisco ACLs and some firewall rules to match address ranges. For a /24 subnet, the subnet mask is 255.255.255.0 and the wildcard mask is 0.0.0.255.
A /24 has 256 total addresses. Subtracting the network address (.0) and broadcast address (.255) leaves 254 usable host addresses — the most common size for a small LAN.
They represent the same thing in different formats. CIDR /24 equals subnet mask 255.255.255.0 — both mean 24 leading network bits. CIDR is compact; dotted-decimal masks are common in router configs.