SubnetPad

/6 Subnet Calculator

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A /6 block contains 67,108,864 addresses — roughly 67 million. Used in RIR address management and seen in routing tables for some large national carriers.

/1
/32

/6 = mask 252.0.0.0 • 67,108,862 usable addresses

Results for 0.0.0.0/6

Reserved (this network)Class A
Network addressThe first address — identifies the subnet itself
Broadcast addressThe last address — used to reach every device at once
Subnet maskSame as /6 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 hosts67,108,864 total addresses in this subnet
More detailsNeighboring subnets, wildcard mask, hex, reverse DNS, and binary breakdown

Neighboring /6 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 address00000000.00000000.00000000.00000000
Subnet mask11111100.00000000.00000000.00000000
Network00000000.00000000.00000000.00000000
Broadcast00000011.11111111.11111111.11111111

Quick facts for /6

/6 reference guideBit split, overview, sizing tables, notable networks, and FAQ

Binary bit split

Network bits (6)Host bits (26)
Network bits
6
Host bits
26
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255
Total addresses
67,108,864
Usable hosts
67,108,862
Hosts formula
2^26 − 2
/24 relationship
262,144 × /24 networks

Overview

A /6 block contains 67,108,864 addresses — roughly 67 million. Used in RIR address management and seen in routing tables for some large national carriers.

Common use cases

  • Regional ISP address space allocation
  • National carrier routing blocks
  • Large-scale network planning

Subnet sizing reference

Divide /6 into…

PrefixSubnetsHosts each
/7233,554,430
/8416,777,214
/988,388,606
/10164,194,302

/6 fits inside…

SupernetHosts/6s inside
/5134,217,7262
/4268,435,4544
/3536,870,9108
/21,073,741,82216

Frequently asked questions

Common questions about /6 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