YurlieCIDR /1 Subnet Reference
A massive IPv4 subnet with 2.147.483.648 total addresses and 2.147.483.646 usable host addresses.
Subnet Mask
128.0.0.0Wildcard Mask
127.255.255.255Total IPs
2.147.483.648Usable Hosts
2.147.483.646Mask (Hex)
80000000Host Bits
31Binary Breakdown
Subnet Mask
10000000.00000000.00000000.00000000Wildcard Mask
01111111.11111111.11111111.11111111Network bits (1s): 1 · Host bits (0s): 31
Common Uses for /1
- Large network segment
- ISP/enterprise allocation
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Enter any IP address with /1 prefix to calculate exact network details.
Frequently Asked Questions
What is the subnet mask for /1?
The subnet mask for /1 is 128.0.0.0 (hex: 80000000). In binary: 10000000.00000000.00000000.00000000.
How many hosts does a /1 subnet support?
A /1 subnet has 2.147.483.648 total addresses. Subtract 2 (network + broadcast) = 2.147.483.646 usable host addresses.
What is the wildcard mask for /1?
The wildcard mask (inverse mask) for /1 is 127.255.255.255. Used in Cisco ACLs and OSPF configurations to match the host portion of an address.
What is CIDR /1 used for?
Large network segment. ISP/enterprise allocation.
Complete CIDR Reference Table /0–/32
| Prefix | Subnet Mask | Wildcard | Total IPs | Usable Hosts |
|---|---|---|---|---|
| /0 | 0.0.0.0 | 255.255.255.255 | 4.294.967.296 | 4.294.967.294 |
| /1 | 128.0.0.0 | 127.255.255.255 | 2.147.483.648 | 2.147.483.646 |
| /2 | 192.0.0.0 | 63.255.255.255 | 1.073.741.824 | 1.073.741.822 |
| /3 | 224.0.0.0 | 31.255.255.255 | 536.870.912 | 536.870.910 |
| /4 | 240.0.0.0 | 15.255.255.255 | 268.435.456 | 268.435.454 |
| /5 | 248.0.0.0 | 7.255.255.255 | 134.217.728 | 134.217.726 |
| /6 | 252.0.0.0 | 3.255.255.255 | 67.108.864 | 67.108.862 |
| /7 | 254.0.0.0 | 1.255.255.255 | 33.554.432 | 33.554.430 |
| /8 | 255.0.0.0 | 0.255.255.255 | 16.777.216 | 16.777.214 |
| /9 | 255.128.0.0 | 0.127.255.255 | 8.388.608 | 8.388.606 |
| /10 | 255.192.0.0 | 0.63.255.255 | 4.194.304 | 4.194.302 |
| /11 | 255.224.0.0 | 0.31.255.255 | 2.097.152 | 2.097.150 |
| /12 | 255.240.0.0 | 0.15.255.255 | 1.048.576 | 1.048.574 |
| /13 | 255.248.0.0 | 0.7.255.255 | 524.288 | 524.286 |
| /14 | 255.252.0.0 | 0.3.255.255 | 262.144 | 262.142 |
| /15 | 255.254.0.0 | 0.1.255.255 | 131.072 | 131.070 |
| /16 | 255.255.0.0 | 0.0.255.255 | 65.536 | 65.534 |
| /17 | 255.255.128.0 | 0.0.127.255 | 32.768 | 32.766 |
| /18 | 255.255.192.0 | 0.0.63.255 | 16.384 | 16.382 |
| /19 | 255.255.224.0 | 0.0.31.255 | 8.192 | 8.190 |
| /20 | 255.255.240.0 | 0.0.15.255 | 4.096 | 4.094 |
| /21 | 255.255.248.0 | 0.0.7.255 | 2.048 | 2.046 |
| /22 | 255.255.252.0 | 0.0.3.255 | 1.024 | 1.022 |
| /23 | 255.255.254.0 | 0.0.1.255 | 512 | 510 |
| /24 | 255.255.255.0 | 0.0.0.255 | 256 | 254 |
| /25 | 255.255.255.128 | 0.0.0.127 | 128 | 126 |
| /26 | 255.255.255.192 | 0.0.0.63 | 64 | 62 |
| /27 | 255.255.255.224 | 0.0.0.31 | 32 | 30 |
| /28 | 255.255.255.240 | 0.0.0.15 | 16 | 14 |
| /29 | 255.255.255.248 | 0.0.0.7 | 8 | 6 |
| /30 | 255.255.255.252 | 0.0.0.3 | 4 | 2 |
| /31 | 255.255.255.254 | 0.0.0.1 | 2 | 2 |
| /32 | 255.255.255.255 | 0.0.0.0 | 1 | 1 |