CIDR / Subnet Calculator

Calculate network address, broadcast address, netmask, and usable host range from CIDR notation. Runs entirely in your browser.

About this calculator

Enter an IPv4 address with a CIDR prefix, e.g. 10.0.0.0/8 or 192.168.1.10/24. For /31 and /32 networks there is no separate network/broadcast pair by convention (RFC 3021), so both addresses in a /31 are shown as usable, and a /32 is a single host.

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About CIDR / Subnet Calculator

CIDR / Subnet Calculator calculates network address, broadcast address, netmask, wildcard mask, and usable IP range from CIDR notation.

How to use CIDR / Subnet Calculator

  1. Enter an IPv4 address with CIDR prefix length (e.g. 192.168.1.0/24).
  2. Click Calculate Subnet to compute network parameters.
  3. Review subnet mask, broadcast IP, total hosts, and usable host range.
  4. Copy subnet parameters for network configuration.

Examples

CIDR: 10.0.0.0/22 Netmask: 255.255.252.0 Usable Host Range: 10.0.0.1 to 10.0.3.254 (1022 hosts)

FAQ

Why are 2 addresses subtracted from total IP addresses?

The network address (first IP) and broadcast address (last IP) cannot be assigned to individual network host interfaces.

Does this calculator support IPv6?

This calculator focuses on IPv4 CIDR subnetting. IPv6 subnet calculation features are available in dedicated IPv6 network tools.

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