CIDR calculator
Enter CIDR notation (10.0.0.0/24) or an IP plus netmask. Get network, broadcast, host range, and a visual split of network vs host bits.
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Network bits (dark) vs host bits
| Network | |
|---|---|
| Prefix | |
| Netmask | |
| Wildcard | |
| Broadcast | |
| First host | |
| Last host | |
| Usable hosts | |
| Network (binary) | |
| Mask (binary) |
IPv6
IPv6 subnetting uses the same prefix idea — /64 is typical on LANs. This tool shows the network portion; host arithmetic on full 128-bit space is left to your IPAM tools.
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I need N hosts
Enter a positive number of hosts.
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About this tool
CIDR notation packs an IP and a prefix length: /24 means 24 network bits and 8 host bits in IPv4. That is 256 addresses, usually 254 usable hosts (/31 and /32 are special cases).
Everything runs locally — paste private network ranges without sending them anywhere.
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