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Runs locally
$ devdesk cidr--local
Security & network

IPv4 CIDR calculator: subnet mask and host range

Calculate IPv4 network, mask, broadcast and usable range for /0–/32. Understand /31 point-to-point and /32 host cases without scanning a network.

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How to use

Enter IPv4/prefix from /0 to /32. /31 uses point-to-point semantics with two usable addresses; /32 represents one host.

Your input stays yours

Step by step

  1. Enter an address and prefix, such as 192.168.1.100/24.
  2. Choose Run to see the network and host range.
  3. Check the actual network context; results do not identify assigned or online devices.

A /24 subnet example

192.168.1.100/24

The network is 192.168.1.0/24, mask 255.255.255.0 and broadcast 192.168.1.255. The conventional usable range is .1 through .254.

Frequently asked questions

Why does /31 show two usable addresses?

The calculator uses IPv4 point-to-point semantics for /31, listing both addresses as usable and no broadcast address. Actual devices and configuration must support this use.

What does /32 mean?

It identifies one IPv4 address, with total and usable counts of 1. Routing and reachability still depend on network configuration.

Does it support IPv6 or network scanning?

It currently calculates IPv4 only. It does not probe devices, send pings or determine whether an address is occupied.

References

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