Subnet / CIDR Calculator
Enter an IP address and CIDR prefix to get the network address, broadcast address, usable host range, and mask.
Network address
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Broadcast address
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Subnet mask
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Wildcard mask
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First usable host
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Last usable host
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Usable hosts
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Notes on edge cases
/31 networks (2 addresses) follow RFC 3021 — both addresses are usable, point-to-point style, with no network/broadcast distinction. /32 is a single host route. These are handled correctly here, not just the common /24-style cases.