SubnetPad

/7 Subnet Calculator

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A /7 block contains 33,554,432 addresses. At this size, blocks represent large swaths of a legacy Class A range and appear in routing tables for major ISPs.

/1
/32

/7 = mask 254.0.0.0 • 33,554,430 usable addresses

Results for 0.0.0.0/7

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 /7 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 hosts33,554,432 total addresses in this subnet
More detailsNeighboring subnets, wildcard mask, hex, reverse DNS, and binary breakdown

Neighboring /7 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 mask11111110.00000000.00000000.00000000
Network00000000.00000000.00000000.00000000
Broadcast00000001.11111111.11111111.11111111

Quick facts for /7

/7 reference guideBit split, overview, sizing tables, notable networks, and FAQ

Binary bit split

Network bits (7)Host bits (25)
Network bits
7
Host bits
25
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255
Total addresses
33,554,432
Usable hosts
33,554,430
Hosts formula
2^25 − 2
/24 relationship
131,072 × /24 networks

Overview

A /7 block contains 33,554,432 addresses. At this size, blocks represent large swaths of a legacy Class A range and appear in routing tables for major ISPs.

Common use cases

  • Major ISP address allocation
  • Legacy Class A range summarization
  • Routing table aggregation

Subnet sizing reference

Divide /7 into…

PrefixSubnetsHosts each
/8216,777,214
/948,388,606
/1084,194,302
/11162,097,150

/7 fits inside…

SupernetHosts/7s inside
/667,108,8622
/5134,217,7264
/4268,435,4548
/3536,870,91016

Frequently asked questions

Common questions about /7 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