IP Subnet Calculator
Use these calculators to inspect IPv4 networks and IPv6 prefixes. All calculations run locally in your browser; addresses are not submitted to the server.
IPv4 Subnet Calculator
IPv6 Prefix Calculator
IPv4 Prefix Reference
| Prefix | Subnet mask | Total addresses | Traditional usable hosts |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
| /16 | 255.255.0.0 | 65,536 | 65,534 |
| /24 | 255.255.255.0 | 256 | 254 |
| /25 | 255.255.255.128 | 128 | 126 |
| /26 | 255.255.255.192 | 64 | 62 |
| /27 | 255.255.255.224 | 32 | 30 |
| /28 | 255.255.255.240 | 16 | 14 |
| /29 | 255.255.255.248 | 8 | 6 |
| /30 | 255.255.255.252 | 4 | 2 |
| /31 | 255.255.255.254 | 2 | 2 on point-to-point links |
| /32 | 255.255.255.255 | 1 | 1 host route |
IPv6 Allocation Perspective
- A typical LAN is assigned a
/64. - A
/56contains 256 separate/64networks. - A
/48contains 65,536 separate/64networks. - Point-to-point links may use
/127where supported and operationally appropriate.