Subnet Calculator
Calculate the network, broadcast, host range, usable hosts, wildcard mask and class for an IPv4 address and prefix.
Runs in your browserIPv4 + CIDR → Subnet details
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How to use the Subnet Calculator
- Type an address with a prefix (10.0.0.0/8) or put the prefix or dotted mask in the second field.
Privacy and limitations
- Your data is processed on your device and is not uploaded to any server.
Frequently asked questions
Why are there two fewer usable hosts than addresses?
The first address identifies the network and the last is the broadcast address. /31 links (RFC 3021) and /32 single hosts are the exceptions.
What is a wildcard mask?
The inverse of the subnet mask (0.0.0.255 for /24). Cisco ACLs and OSPF use it to say which bits may vary.
Related converters
CIDR to IP Range ConverterConvert CIDR notation like 10.0.0.0/8 or 2001:db8::/32 into the first and last address and the address count.IP Range to CIDR ConverterConvert an IP address range into the smallest list of CIDR blocks that covers it exactly, for IPv4 or IPv6.IP to Binary ConverterConvert IP addresses to binary, shown as dotted octets for IPv4 or 16-bit groups for IPv6.Hex to IP ConverterConvert hexadecimal values such as 0xC0A80101 or C0.A8.01.01 to IPv4, or 32 hex digits to IPv6.IP to Hex ConverterConvert IP addresses to hexadecimal, as plain hex, 0x-prefixed or dotted bytes (C0.A8.01.01).IPv6 ExpanderExpand shortened IPv6 addresses to the full eight groups of four hex digits.Binary to IP ConverterConvert 32-bit or dotted binary values to IPv4 addresses, or 128-bit binary values to IPv6.IPv6 CompressorShorten IPv6 addresses to the canonical RFC 5952 form: lowercase, no leading zeros, longest zero run as ::.