IPv4 Subnet Calculator
Enter any IPv4 address in CIDR notation. Results update as you type.
Examples:
10.10.20.0/24, 172.16.0.0/12, 192.168.1.55 (bare IP treated as /32)
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Enter a CIDR address above to see results
Common subnet reference
| Prefix | Subnet mask | Usable hosts | Common use |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 | Class A network |
| /16 | 255.255.0.0 | 65,534 | Class B / large campus |
| /20 | 255.255.240.0 | 4,094 | Large VLAN |
| /22 | 255.255.252.0 | 1,022 | Large VLAN |
| /23 | 255.255.254.0 | 510 | Medium VLAN |
| /24 | 255.255.255.0 | 254 | Standard VLAN (most common) |
| /25 | 255.255.255.128 | 126 | Half subnet |
| /26 | 255.255.255.192 | 62 | Small VLAN |
| /27 | 255.255.255.224 | 30 | Point-to-point segment |
| /28 | 255.255.255.240 | 14 | Management / OOB network |
| /29 | 255.255.255.248 | 6 | Small server subnet |
| /30 | 255.255.255.252 | 2 | Point-to-point link |
| /31 | 255.255.255.254 | 2 | P2P link (RFC 3021) |
| /32 | 255.255.255.255 | 1 | Host route / loopback |
