IP & Netmask
Enter an IPv4 address and prefix/netmask.
Subnet Details
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Supported masks: prefix lengths from /0 to /32, dotted decimal masks such as 255.255.255.0, and wildcard masks such as 0.0.0.255.
Usable hosts: /31 networks have 2 usable addresses per RFC 3021, and /32 networks have 1 address.
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Subnet Math

Get network, broadcast, first/last usable address, wildcard mask and host counts instantly.

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CIDR & Masks

Use a CIDR prefix, dotted decimal netmask, or a wildcard mask. Invalid masks are rejected.

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All calculations run locally in your browser. No IP address is uploaded.