A /11 fixes 11 bits, so the second octet moves in steps of 32 (0–31, 32–63 and so on). It holds about two million addresses. Networks this large appear as ISP and cloud allocations or as summary routes, not as subnets anyone puts devices into. Subnetting exercises use it to practise the block-size method on the second octet.
Facts
- Prefix
- /11
- Subnet mask
- 255.224.0.0
- Wildcard mask
- 0.31.255.255
- Binary mask
- 11111111.11100000.00000000.00000000
- Total addresses
- 2,097,152
- Usable hosts
- 2,097,150
- Example range
- 10.0.0.0/11: 10.0.0.0 – 10.31.255.255
- Typical use
- Large ISP allocations.
Try it
Try: , ,
- CIDR block
- 10.0.0.0/11
- IP range
- 10.0.0.0 – 10.31.255.255
- Addresses
- 2,097,152
- Usable hosts
- 2,097,150
- Subnet mask
- 255.224.0.0
- Wildcard mask
- 0.31.255.255
Frequently asked questions
How many hosts are in a /11?
A /11 has 2,097,152 addresses. Subtracting the network and broadcast addresses leaves 2,097,150 usable hosts.
What is the subnet mask for /11?
/11 is 255.224.0.0 (wildcard mask 0.31.255.255). In binary that’s 11 ones followed by 21 zeros.