Subnet Cheat Sheet
Quick IPv4 subnetting reference for CIDR prefixes, subnet masks, wildcard masks, address counts, and common private ranges.
Common IPv4 CIDR Blocks
| CIDR | Subnet Mask | Wildcard Mask | Usable Hosts | Typical Use |
|---|---|---|---|---|
| /30 | 255.255.255.252 | 0.0.0.3 | 2 | Point-to-point link |
| /29 | 255.255.255.248 | 0.0.0.7 | 6 | Small device segment |
| /28 | 255.255.255.240 | 0.0.0.15 | 14 | Small branch network |
| /27 | 255.255.255.224 | 0.0.0.31 | 30 | Department VLAN |
| /26 | 255.255.255.192 | 0.0.0.63 | 62 | Medium LAN |
| /25 | 255.255.255.128 | 0.0.0.127 | 126 | Large VLAN |
| /24 | 255.255.255.0 | 0.0.0.255 | 254 | Standard LAN |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,534 | Large private network |
Private IPv4 Ranges
10.0.0.0/810.0.0.0 through 10.255.255.255
172.16.0.0/12172.16.0.0 through 172.31.255.255
192.168.0.0/16192.168.0.0 through 192.168.255.255