/5 Subnet
Subnet Mask
Wildcard Mask
7.255.255.255
Total IPs
134,217,728
Usable Hosts
134,217,726
Network Bits
5
Host Bits
27
About /5 Networks
Extremely large allocation, rarely used outside global routing. A /5 subnet uses the mask 248.0.0.0 and provides 134,217,726 usable host addresses out of 134,217,728 total IPs.
Example /5 Networks
| Network | Broadcast | First Host | Last Host |
|---|---|---|---|
| 8.0.0.0/5 | 15.255.255.255 | 8.0.0.1 | 15.255.255.254 |
| 168.0.0.0/5 | 175.255.255.255 | 168.0.0.1 | 175.255.255.254 |
| 192.0.0.0/5 | 199.255.255.255 | 192.0.0.1 | 199.255.255.254 |
| 192.0.0.0/5 | 199.255.255.255 | 192.0.0.1 | 199.255.255.254 |
| 8.0.0.0/5 | 15.255.255.255 | 8.0.0.1 | 15.255.255.254 |
Splitting a /5 Into Smaller Subnets
A /5 divides evenly into any longer prefix. Each row shows how many subnets of that size fit inside one /5, and how many usable hosts each of them carries.
| Subnet Size | How Many Fit | Mask | Usable Hosts Each |
|---|---|---|---|
| /6 | 2 × /6 | 252.0.0.0 | 67,108,862 |
| /7 | 4 × /7 | 254.0.0.0 | 33,554,430 |
| /8 | 8 × /8 | 255.0.0.0 | 16,777,214 |
| /9 | 16 × /9 | 255.128.0.0 | 8,388,606 |
| /10 | 32 × /10 | 255.192.0.0 | 4,194,302 |
| /11 | 64 × /11 | 255.224.0.0 | 2,097,150 |
| /12 | 128 × /12 | 255.240.0.0 | 1,048,574 |
| /13 | 256 × /13 | 255.248.0.0 | 524,286 |
| /14 | 512 × /14 | 255.252.0.0 | 262,142 |
| /15 | 1,024 × /15 | 255.254.0.0 | 131,070 |
| /16 | 2,048 × /16 | 255.255.0.0 | 65,534 |
| /17 | 4,096 × /17 | 255.255.128.0 | 32,766 |
| /18 | 8,192 × /18 | 255.255.192.0 | 16,382 |
| /19 | 16,384 × /19 | 255.255.224.0 | 8,190 |
| /20 | 32,768 × /20 | 255.255.240.0 | 4,094 |
| /21 | 65,536 × /21 | 255.255.248.0 | 2,046 |
| /22 | 131,072 × /22 | 255.255.252.0 | 1,022 |
| /23 | 262,144 × /23 | 255.255.254.0 | 510 |
| /24 | 524,288 × /24 | 255.255.255.0 | 254 |
| /25 | 1,048,576 × /25 | 255.255.255.128 | 126 |
| /26 | 2,097,152 × /26 | 255.255.255.192 | 62 |
| /27 | 4,194,304 × /27 | 255.255.255.224 | 30 |
| /28 | 8,388,608 × /28 | 255.255.255.240 | 14 |
| /29 | 16,777,216 × /29 | 255.255.255.248 | 6 |
| /30 | 33,554,432 × /30 | 255.255.255.252 | 2 |
| /31 | 67,108,864 × /31 | 255.255.255.254 | 2 |
| /32 | 134,217,728 × /32 | 255.255.255.255 | 1 |
How Many /5 Subnets Fit in a Larger Network
The same arithmetic read the other way: how many /5 subnets you get when you carve up each of the next larger prefixes.
Adjacent CIDRs
Frequently Asked Questions
What is a /5 subnet?
A /5 subnet uses the subnet mask 248.0.0.0 with 134,217,726 usable host addresses and 134,217,728 total IP addresses. It has 5 network bits and 27 host bits.
How many hosts in a /5 network?
A /5 network supports 134,217,726 usable hosts out of 134,217,728 total IP addresses. The usable range excludes the network address and broadcast address.
What subnet mask does /5 use?
A /5 subnet uses the mask 248.0.0.0 (wildcard mask 7.255.255.255). This means the first 5 bits identify the network and the remaining 27 bits identify hosts.
How many /7 subnets are in a /5?
One /5 splits into 4 /7 subnets, each with mask 254.0.0.0 and 33,554,430 usable hosts. Every prefix longer than /5 divides it evenly — the full table is above.
How many /5 subnets are in a /4?
A /4 holds 2 /5 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.
- RFC 4632 — Classless Inter-Domain Routing (CIDR)
Defines the /5 prefix notation used throughout this page, and the address-aggregation model that replaced classful addressing.
- RFC 950 — Internet Standard Subnetting Procedure
The original definition of the subnet mask, and of the network and broadcast addresses excluded from the usable host count.