CIDR prefix
/7
254.0.0.0
33,554,430 usable hosts · 33,554,432 addresses
The mask for /7 is 254.0.0.0 — 33,554,432 addresses, 33,554,430 usable hosts. Huge blocks used only by registries and carriers.
Mask
254.0.0.0
Wildcard
1.255.255.255
Addresses
33,554,432
Hosts
33,554,430
Worked example: 10.0.0.0/7
Network address10.0.0.0/7
Broadcast address11.255.255.255
First host10.0.0.1
Last host11.255.255.254
FAQ — /7
What is the subnet mask for /7?
The subnet mask for /7 is 254.0.0.0 (wildcard: 1.255.255.255). The first 7 bits are the network part, the remaining 25 are the host part.
How many hosts fit in a /7?
A /7 block holds 33,554,432 addresses, of which 33,554,430 are usable hosts (the network and broadcast addresses are excluded).
What is a /7 used for?
Huge blocks used only by registries and carriers.