IP Subnet Calculator
Work out the network, broadcast, netmask, host range and size of any IPv4 or IPv6 subnet.
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By MegaHostZone · AS132563
How to use the subnet calculator
Enter an IP address with its prefix length or mask. Any of these formats work:
- CIDR –
192.168.1.10/24or2001:db8:1234::/48 - Netmask –
10.0.0.1 255.255.252.0 - Wildcard mask –
10.0.0.1 0.0.3.255(as used in Cisco ACLs)
The network address is the first address of the subnet and the broadcast address the last; in IPv4 the addresses in between are the usable hosts. A /31 is a special case for point-to-point links (RFC 3021) where both addresses are usable, and a /32 is a single host. IPv6 has no broadcast address, and a /64 is the standard size for a single LAN.
IPv4 CIDR quick reference
| Prefix | Netmask | Addresses | Usable hosts |
|---|---|---|---|
| /32 | 255.255.255.255 | 1 | 1 |
| /31 | 255.255.255.254 | 2 | 2 |
| /30 | 255.255.255.252 | 4 | 2 |
| /29 | 255.255.255.248 | 8 | 6 |
| /28 | 255.255.255.240 | 16 | 14 |
| /27 | 255.255.255.224 | 32 | 30 |
| /26 | 255.255.255.192 | 64 | 62 |
| /25 | 255.255.255.128 | 128 | 126 |
| /24 | 255.255.255.0 | 256 | 254 |
| /23 | 255.255.254.0 | 512 | 510 |
| /22 | 255.255.252.0 | 1,024 | 1,022 |
| /21 | 255.255.248.0 | 2,048 | 2,046 |
| /20 | 255.255.240.0 | 4,096 | 4,094 |
| /19 | 255.255.224.0 | 8,192 | 8,190 |
| /18 | 255.255.192.0 | 16,384 | 16,382 |
| /17 | 255.255.128.0 | 32,768 | 32,766 |
| /16 | 255.255.0.0 | 65,536 | 65,534 |
| /15 | 255.254.0.0 | 131,072 | 131,070 |
| /14 | 255.252.0.0 | 262,144 | 262,142 |
| /13 | 255.248.0.0 | 524,288 | 524,286 |
| /12 | 255.240.0.0 | 1,048,576 | 1,048,574 |
| /11 | 255.224.0.0 | 2,097,152 | 2,097,150 |
| /10 | 255.192.0.0 | 4,194,304 | 4,194,302 |
| /9 | 255.128.0.0 | 8,388,608 | 8,388,606 |
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
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