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CIDR to IP range calculator

Convert CIDR notation to an IP range: first and last address, netmask, wildcard mask, total and usable hosts for IPv4 and IPv6. Runs in your browser.

/n→NETWORK PLANNING

CIDR to IP range calculator

Convert an IPv4 or IPv6 CIDR block to its first and last address, netmask, wildcard mask and address counts.

Calculated locally in this browser with exact integer arithmetic (128-bit for IPv6). No network request is made and the input is not saved.

Enter a CIDR block such as 10.0.0.0/16 or 2001:db8::/48.

Planning aid only. It does not know your routes, reserved ranges, cloud provider rules or authoritative IP address plan. IPv4 usable hosts exclude the network and broadcast addresses except on /31 and /32. To go the other way, use the IP range to CIDR converter; the subnet mask and prefix length cheat sheet lists every prefix.

Use this result carefully

Convert CIDR notation to an IP range: first and last address, netmask, wildcard mask, total and usable hosts for IPv4 and IPv6. Runs in your browser.

Review the limits and privacy notes shown with the tool. Important configuration or security decisions should be checked against authoritative systems and your organization’s approved procedures.

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