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Subnet Calculator: IPv4 CIDR, Netmask, Hosts and Ranges

Enter an IPv4 address with a prefix or netmask to get the network, broadcast, host range, wildcard mask and usable hosts. Split into subnets.

Type an address with a prefix (192.168.1.10/24) or a netmask (192.168.1.10 255.255.255.0). The result shows the network, the first and last usable address, the broadcast address and how many hosts fit. You can also split the network into equal subnets.

Examples: 10.0.0.5/16 or 192.168.1.10 255.255.255.0

Common prefixes

PrefixNetmaskAddressesUsable hosts
/8255.0.0.016,777,21616,777,214
/16255.255.0.065,53665,534
/24255.255.255.0256254
/25255.255.255.128128126
/26255.255.255.1926462
/27255.255.255.2243230
/28255.255.255.2401614
/29255.255.255.24886
/30255.255.255.25242

Frequently asked questions

How many usable hosts does a /24 have?
254. A /24 has 256 addresses, and the first (network) and last (broadcast) are not usable for hosts.
What is the difference between a netmask and a prefix?
255.255.255.0 and /24 mean the same thing. The prefix counts the leading 1 bits in the netmask.
What about /31 and /32?
A /31 has two usable addresses for point-to-point links (RFC 3021), and a /32 is a single host.
Does it work for IPv6?
Not yet. This calculator handles IPv4 only.

Runs in your browser. Nothing you type is sent to this site. Updated 2026-10-03.

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