Subnet Mask
/19 Subnet Mask
A /19 prefix means the subnet mask is 255.255.224.0. It has 13 host bits, giving 8,192 total addresses and 8,190 usable hosts.
/19 at a glance
| Property | Value |
|---|---|
| CIDR prefix | /19 |
| Subnet mask | 255.255.224.0 |
| Wildcard mask | 0.0.31.255 |
| Total addresses | 8,192 |
| Usable hosts | 8,190 |
| Host bits | 13 |
How it is calculated
A /19 sets the first 19 bits to 1 (network) and the remaining 13 bits to 0 (host). Usable hosts = 213 − 2 = 8,190.
The wildcard mask 0.0.31.255 is the inverse — used in Cisco ACLs and OSPF network statements.
Frequently asked questions
What is a /19 subnet mask?
A /19 equals 255.255.224.0 in dotted decimal (wildcard 0.0.31.255). It provides 8,192 total addresses and 8,190 usable hosts.
How many hosts are in a /19?
A /19 has 13 host bits, so it supports 8,190 usable hosts.
What is the wildcard mask for /19?
The wildcard (inverse) mask for /19 is 0.0.31.255, used in Cisco ACLs and OSPF statements.
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