IPv4 subnet calculator

Get the network, broadcast, mask, and usable range for an IPv4 CIDR block.

e.g. 192.168.1.10/24 — or enter an address like 192.168.1.10 and a mask like 255.255.255.0

e.g. 255.255.255.0 or /24 — blank means /24

Everything is calculated in this browser.

How to use

  1. Enter an address with a prefix, like 192.168.1.10/24, or an address plus a subnet mask.
  2. Run the calculation.
  3. Read the network details.

What it supports

IPv4 only. A bare address defaults to /24; masks must be contiguous. /31 links follow RFC 3021 (two usable addresses, no broadcast) and /32 is a single host.

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