60 ? '~' . number_format(pow(2, min($host_bits, 63)), 0, ',', '.') . ' (huge)' : number_format(pow(2, $host_bits), 0, ',', '.'); $type = 'Global Unicast'; if ($ip === '::1') $type = 'Loopback'; elseif (str_starts_with($ip_bin, '11111110100')) $type = 'Link-Local (fe80::/10)'; elseif (str_starts_with($ip_bin, '11111100')) $type = 'Unique Local (fc00::/7)'; elseif (str_starts_with($ip_bin, '11111111')) $type = 'Multicast (ff00::/8)'; return [ 'ip' => $ip, 'prefix' => $prefix, 'cidr' => $ip . '/' . $prefix, 'network' => bin_to_ipv6($net_bin), 'broadcast' => bin_to_ipv6($bc_bin), 'first_host' => bin_to_ipv6(substr($net_bin, 0, 127) . '1'), 'last_host' => bin_to_ipv6(substr($bc_bin, 0, 127) . '0'), 'mask' => bin_to_ipv6($mask_bin), 'hosts' => $hosts, 'host_bits' => $host_bits, 'type' => $type, ]; } if ($query) { $raw_ip = preg_replace('/\/\d+$/', '', $query); $raw_ip = trim($raw_ip); if (filter_var($raw_ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6)) { $is_ipv6 = true; $ip = $raw_ip; if ($get_prefix !== null) $prefix = $get_prefix; elseif (str_contains($query, '/')) { [, $pfx] = explode('/', $query, 2); $prefix = (int)$pfx; } else $prefix = 64; $prefix = max(0, min(128, $prefix)); $result = ipv6_subnet_calc($ip, $prefix); if (!$result) $error = 'Invalid IPv6 address.'; } elseif (filter_var($raw_ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) { $ip = $raw_ip; if ($get_prefix !== null) $prefix = $get_prefix; elseif (str_contains($query, '/')) { [, $pfx] = explode('/', $query, 2); $prefix = (int)$pfx; } else $prefix = 24; $prefix = max(0, min(32, $prefix)); if ($prefix < 0 || $prefix > 32) { $error = 'Invalid prefix. Allowed range: /0 to /32.'; } else { $mask_long = $prefix > 0 ? (0xFFFFFFFF << (32 - $prefix)) & 0xFFFFFFFF : 0; $ip_long = ip2long($ip); $net_long = $ip_long & $mask_long; $bc_long = $net_long | (~$mask_long & 0xFFFFFFFF); $hosts_total = $prefix <= 30 ? pow(2, 32 - $prefix) : ($prefix === 31 ? 2 : 1); $hosts_usable = $prefix <= 30 ? $hosts_total - 2 : ($prefix === 31 ? 2 : 1); $wildcard = long2ip(~$mask_long & 0xFFFFFFFF); $first = (int)explode('.', $ip)[0]; $class = match(true) { $first < 128 => 'A', $first < 192 => 'B', $first < 224 => 'C', $first < 240 => 'D (Multicast)', default => 'E (Reserved)', }; $ip_bin = implode('.', array_map(fn($o) => sprintf('%08b', $o), explode('.', $ip))); $mask_bin = implode('.', array_map(fn($o) => sprintf('%08b', $o), explode('.', long2ip($mask_long)))); $subnets = []; if ($prefix < 29) { $sub_size = pow(2, 32 - ($prefix + 3)); for ($i = 0; $i < 8; $i++) { $sub_net = $net_long + ($i * $sub_size); $sub_bc = $sub_net + $sub_size - 1; $subnets[] = [ 'network' => long2ip($sub_net) . '/' . ($prefix + 3), 'first_host' => long2ip($sub_net + 1), 'last_host' => long2ip($sub_bc - 1), 'broadcast' => long2ip($sub_bc), ]; } } $result = [ 'ip' => $ip, 'prefix' => $prefix, 'cidr' => $ip . '/' . $prefix, 'network' => long2ip($net_long), 'broadcast' => long2ip($bc_long), 'first_host' => long2ip($net_long + 1), 'last_host' => long2ip($bc_long - 1), 'netmask' => long2ip($mask_long), 'wildcard' => $wildcard, 'hosts_total' => number_format($hosts_total, 0, ',', '.'), 'hosts_usable' => number_format(max(0, $hosts_usable), 0, ',', '.'), 'class' => $class, 'ip_bin' => $ip_bin, 'mask_bin' => $mask_bin, 'is_private' => is_private_ip($ip), 'subnets' => $subnets, ]; } } else { $error = 'Invalid IP address. Please enter an IPv4 (e.g. 192.168.1.0) or IPv6 (e.g. 2001:db8::) address.'; } } $current_prefix = $result['prefix'] ?? $get_prefix ?? ($is_ipv6 ? 64 : 24); require_once __DIR__ . '/header.php'; ?>
Tool
IP Subnet Calculator
IPv4 and IPv6 – Calculate network address, subnet mask and host range
IPv4 IPv6
/
Prefix Length
Addresses
Host Bits
Address Type
Network Information
CIDR
Network address
First host
Last host
Total addresses
Details
Subnet mask
Prefix length/
Host bits
Type
/
Prefix Length
Usable Hosts
Class
IP Class
IP Type
Network Information
CIDR notation
Network address
Broadcast
First host
Last host
Total hosts
Usable hosts
Subnet Details
Subnet mask
Wildcard mask
Prefix length/
IP classClass
TypePrivate / RFC1918' : 'Public' ?>
Binary representation
IP address
Subnet mask
Possible subnets / (first 8)
$sub): ?>
#NetworkFirst HostLast HostBroadcast
Enter an IPv4 or IPv6 address with prefix, e.g. 192.168.1.0/24 or 2001:db8::/32.
IPv4 Examples
IPv6 Examples
My IP Subnet IP Lookup IPv4 Detail IPv6 Detail

IPv4 and IPv6 Subnet Calculator

The subnet calculator supports both IPv4 (CIDR /0–/32) and IPv6 (CIDR /0–/128). Simply enter the IP address – the tool automatically detects whether it is IPv4 or IPv6. For IPv4, the network address, broadcast, first and last host, subnet mask, wildcard mask and possible subnets are calculated. For IPv6, the network address, prefix length and address type are shown.