Subnet mask and prefix length chart
Look up the subnet mask, wildcard mask, address count and usable hosts for every IPv4 prefix length from /0 to /32, plus common IPv6 prefixes.
Quick answers: /24 is 255.255.255.0 (256 addresses, 254 usable); /25 is 255.255.255.128 (128 addresses); /26 is 255.255.255.192 (64 addresses, 62 usable); /16 is 255.255.0.0 (65,536 addresses); /15 is 255.254.0.0 (131,072 addresses).
The chart is generated in your browser from the prefix length. Nothing is sent and the search is not saved.
| Prefix | Subnet mask | Wildcard mask | Total addresses | Usable hosts |
|---|
| Prefix | Total addresses | /64 subnets | Typical use |
|---|
Usable hosts follow the traditional IPv4 rule: the network and broadcast addresses are excluded, except /31 (two addresses on a point-to-point link) and /32 (one host). Your platform or cloud provider may reserve more addresses. IPv6 has no broadcast address and the table shows only common sizes; use the IPv6 subnet calculator for any other prefix or the CIDR to IP range calculator to turn a block into its first and last address.