DNSlens

Subnet calculator

Give it an address and a prefix, in whichever notation you have to hand. The /31 and /32 cases are handled properly, and IPv6 counts are exact rather than rounded into scientific notation.

Worked out in your browser as you type. This tool makes no network request of any kind.

192.168.1.0/24

private range
Network
192.168.1.0
Broadcast
192.168.1.255
Host range
192.168.1.1 – 192.168.1.254
Subnet mask
255.255.255.0
Wildcard
0.0.0.255
Addresses
254 usable of 256 in the block
Legacy class
C — historical; routing has been classless since 1993

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Worth knowing

  • A /24 is 254 usable addresses, not 256: the first is the network address and the last is the broadcast address.
  • A /31 is the exception — RFC 3021 gives it two usable addresses, because a point-to-point link has no use for a broadcast address.
  • Class A, B and C stopped governing routing in 1993 when CIDR arrived. The class is shown because people still say it, not because anything depends on it.