SubnetPad

/11 Subnet Calculator

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A /11 block contains 2,097,152 addresses. Used for large organizational address spaces split from RFC 1918 blocks.

/1
/32

/11 = mask 255.224.0.0 • 2,097,150 usable addresses

Results for 10.0.0.0/11

Private (RFC 1918)Class A
Network addressThe first address — identifies the subnet itself
Broadcast addressThe last address — used to reach every device at once
Subnet maskSame as /11 in CIDR notation
First usable hostThe first IP you can assign to a device
Last usable hostThe last IP you can assign to a device
Usable hosts2,097,152 total addresses in this subnet
More detailsNeighboring subnets, wildcard mask, hex, reverse DNS, and binary breakdown

Neighboring /11 subnets

Wildcard mask
Used in Cisco ACLs and OSPF
CIDR notation
IP in hexadecimal
IP as 32-bit integer
Reverse DNS (PTR)
Host bits / subnet bits

Binary breakdown

IP address00001010.00000000.00000000.00000000
Subnet mask11111111.11100000.00000000.00000000
Network00001010.00000000.00000000.00000000
Broadcast00001010.00011111.11111111.11111111

Quick facts for /11

/11 reference guideBit split, overview, sizing tables, notable networks, and FAQ

Binary bit split

Network bits (11)Host bits (21)
Network bits
11
Host bits
21
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255
Total addresses
2,097,152
Usable hosts
2,097,150
Hosts formula
2^21 − 2
/24 relationship
8,192 × /24 networks

Overview

A /11 block contains 2,097,152 addresses. Used for large organizational address spaces split from RFC 1918 blocks.

Common use cases

  • Large corporate global address plans
  • Service provider customer aggregation
  • Data center super-aggregation blocks

Subnet sizing reference

Divide /11 into…

PrefixSubnetsHosts each
/1221,048,574
/134524,286
/148262,142
/1516131,070

/11 fits inside…

SupernetHosts/11s inside
/104,194,3022
/98,388,6064
/816,777,2148
/733,554,43016

Frequently asked questions

Common questions about /11 networks, subnet masks, and use cases.

All CIDR prefix sizes

/0/1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19/20/21/22/23/24/25/26/27/28/29/30/31/32