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/7 Subnet

A /7 has the subnet mask 254.0.0.0 and contains 33,554,432 IP addresses, of which 33,554,430 are usable hosts. Every other prefix is in the subnet cheat sheet.

Subnet Mask

254.0.0.0

Wildcard Mask

1.255.255.255

Total IPs

33,554,432

Usable Hosts

33,554,430

Network Bits

7

Host Bits

25

All 32 /7 Ranges in a /2

0.0.0.0/2 divides into 32 /7 subnets of 33,554,432 addresses each. The same pattern repeats in any /2: only the leading octets change.

NetworkUsable RangeBroadcast
0.0.0.0/70.0.0.1 – 1.255.255.2541.255.255.255
2.0.0.0/72.0.0.1 – 3.255.255.2543.255.255.255
4.0.0.0/74.0.0.1 – 5.255.255.2545.255.255.255
6.0.0.0/76.0.0.1 – 7.255.255.2547.255.255.255
8.0.0.0/78.0.0.1 – 9.255.255.2549.255.255.255
10.0.0.0/710.0.0.1 – 11.255.255.25411.255.255.255
12.0.0.0/712.0.0.1 – 13.255.255.25413.255.255.255
14.0.0.0/714.0.0.1 – 15.255.255.25415.255.255.255
16.0.0.0/716.0.0.1 – 17.255.255.25417.255.255.255
18.0.0.0/718.0.0.1 – 19.255.255.25419.255.255.255
20.0.0.0/720.0.0.1 – 21.255.255.25421.255.255.255
22.0.0.0/722.0.0.1 – 23.255.255.25423.255.255.255
24.0.0.0/724.0.0.1 – 25.255.255.25425.255.255.255
26.0.0.0/726.0.0.1 – 27.255.255.25427.255.255.255
28.0.0.0/728.0.0.1 – 29.255.255.25429.255.255.255
30.0.0.0/730.0.0.1 – 31.255.255.25431.255.255.255
32.0.0.0/732.0.0.1 – 33.255.255.25433.255.255.255
34.0.0.0/734.0.0.1 – 35.255.255.25435.255.255.255
36.0.0.0/736.0.0.1 – 37.255.255.25437.255.255.255
38.0.0.0/738.0.0.1 – 39.255.255.25439.255.255.255
40.0.0.0/740.0.0.1 – 41.255.255.25441.255.255.255
42.0.0.0/742.0.0.1 – 43.255.255.25443.255.255.255
44.0.0.0/744.0.0.1 – 45.255.255.25445.255.255.255
46.0.0.0/746.0.0.1 – 47.255.255.25447.255.255.255
48.0.0.0/748.0.0.1 – 49.255.255.25449.255.255.255
50.0.0.0/750.0.0.1 – 51.255.255.25451.255.255.255
52.0.0.0/752.0.0.1 – 53.255.255.25453.255.255.255
54.0.0.0/754.0.0.1 – 55.255.255.25455.255.255.255
56.0.0.0/756.0.0.1 – 57.255.255.25457.255.255.255
58.0.0.0/758.0.0.1 – 59.255.255.25459.255.255.255
60.0.0.0/760.0.0.1 – 61.255.255.25461.255.255.255
62.0.0.0/762.0.0.1 – 63.255.255.25463.255.255.255

About /7 Networks

Extremely large allocation, rarely used outside global routing. A /7 subnet uses the mask 254.0.0.0 and provides 33,554,430 usable host addresses out of 33,554,432 total IPs.

Example /7 Networks

NetworkBroadcastFirst HostLast Host
10.0.0.0/711.255.255.25510.0.0.111.255.255.254
172.0.0.0/7173.255.255.255172.0.0.1173.255.255.254
192.0.0.0/7193.255.255.255192.0.0.1193.255.255.254
192.0.0.0/7193.255.255.255192.0.0.1193.255.255.254
8.0.0.0/79.255.255.2558.0.0.19.255.255.254

Splitting a /7 Into Smaller Subnets

A /7 divides evenly into any longer prefix. Each row shows how many subnets of that size fit inside one /7, and how many usable hosts each of them carries.

Subnet SizeHow Many FitMaskUsable Hosts Each
/82 × /8255.0.0.016,777,214
/94 × /9255.128.0.08,388,606
/108 × /10255.192.0.04,194,302
/1116 × /11255.224.0.02,097,150
/1232 × /12255.240.0.01,048,574
/1364 × /13255.248.0.0524,286
/14128 × /14255.252.0.0262,142
/15256 × /15255.254.0.0131,070
/16512 × /16255.255.0.065,534
/171,024 × /17255.255.128.032,766
/182,048 × /18255.255.192.016,382
/194,096 × /19255.255.224.08,190
/208,192 × /20255.255.240.04,094
/2116,384 × /21255.255.248.02,046
/2232,768 × /22255.255.252.01,022
/2365,536 × /23255.255.254.0510
/24131,072 × /24255.255.255.0254
/25262,144 × /25255.255.255.128126
/26524,288 × /26255.255.255.19262
/271,048,576 × /27255.255.255.22430
/282,097,152 × /28255.255.255.24014
/294,194,304 × /29255.255.255.2486
/308,388,608 × /30255.255.255.2522
/3116,777,216 × /31255.255.255.2542
/3233,554,432 × /32255.255.255.2551

How Many /7 Subnets Fit in a Larger Network

The same arithmetic read the other way: how many /7 subnets you get when you carve up each of the next larger prefixes.

Parent Network/7 SubnetsMaskTotal IPs
/62 × /7252.0.0.067,108,864
/54 × /7248.0.0.0134,217,728
/48 × /7240.0.0.0268,435,456
/316 × /7224.0.0.0536,870,912
/232 × /7192.0.0.01,073,741,824
/164 × /7128.0.0.02,147,483,648
/0128 × /70.0.0.04,294,967,296

Adjacent CIDRs

Larger network

/6

Mask: 252.0.0.0

Total IPs: 67,108,864

Usable Hosts: 67,108,862

Smaller network

/8

Mask: 255.0.0.0

Total IPs: 16,777,216

Usable Hosts: 16,777,214

Comparing sizes? The full /0 to /32 cheat sheet table puts every prefix side by side.

Frequently Asked Questions

What is a /7 subnet?

A /7 subnet uses the subnet mask 254.0.0.0 with 33,554,430 usable host addresses and 33,554,432 total IP addresses. It has 7 network bits and 25 host bits.

How many IP addresses are in a /7?

A /7 contains 33,554,432 IP addresses, of which 33,554,430 are usable hosts. The network address and the broadcast address are the two that cannot be assigned to a host.

What subnet mask does /7 use?

A /7 subnet uses the mask 254.0.0.0 (wildcard mask 1.255.255.255). This means the first 7 bits identify the network and the remaining 25 bits identify hosts.

How many /9 subnets are in a /7?

One /7 splits into 4 /9 subnets, each with mask 255.128.0.0 and 8,388,606 usable hosts. Every prefix longer than /7 divides it evenly — the full table is above.

How many /7 subnets are in a /6?

A /6 holds 2 /7 subnets. Each step to a shorter prefix doubles that count, because one bit moves from the host portion of the address to the network portion.

Standards

The figures on this page follow from the following specifications rather than from convention.

Calculate 192.168.0.0/7 →