IPv4 TCP-IP Subnet Table
Please note: Certain potions of the IPv4 address space are specifically allocated by RFCs for special uses; such as loopback (RFC 1643), private networks (RFC 1918), and zeroconf (RFC 3927) usage.
* Usable Hosts – (2^N-2) method.
** Inverse mask is calculated by subtracting each subnet mask octet value from 255.
The inverse mask is primarily used in Cisco access control lists (ACLs).
Address ranges below are reserved by IANA for private intranets, and not routable to the Internet. For additional information, see RFC 1918.
Subnet Mask (Netmask) | Binary | CIDR | Hosts* | Inverse Mask** |
255.255.255.255 | 11111111.11111111.11111111.11111111 | /32 | 1 | 0.0.0.0 |
255.255.255.254 | 11111111.11111111.11111111.11111110 | /31 | 0 | |
255.255.255.252 | 11111111.11111111.11111111.11111100 | /30 | 2 | 0.0.0.3 |
255.255.255.248 | 11111111.11111111.11111111.11111000 | /29 | 6 | 0.0.0.7 |
255.255.255.240 | 11111111.11111111.11111111.11110000 | /28 | 14 | 0.0.0.15 |
255.255.255.224 | 11111111.11111111.11111111.11100000 | /27 | 30 | 0.0.0.31 |
255.255.255.192 | 11111111.11111111.11111111.11000000 | /26 | 62 | 0.0.0.63 |
255.255.255.128 | 11111111.11111111.11111111.10000000 | /25 | 126 | 0.0.0.127 |
255.255.255.0 | 11111111.11111111.11111111.00000000 | /24 | 254 | 0.0.0.255 |
255.255.254.0 | 11111111.11111111.11111110.00000000 | /23 | 510 | 0.0.1.255 |
255.255.252.0 | 11111111.11111111.11111100.00000000 | /22 | 1022 | 0.0.3.255 |
255.255.248.0 | 11111111.11111111.11111000.00000000 | /21 | 2046 | 0.0.7.255 |
255.255.240.0 | 11111111.11111111.11110000.00000000 | /20 | 4094 | 0.0.15.255 |
255.255.224.0 | 11111111.11111111.11100000.00000000 | /19 | 8190 | 0.0.31.255 |
255.255.192.0 | 11111111.11111111.11000000.00000000 | /18 | 16382 | 0.0.63.255 |
255.255.128.0 | 11111111.11111111.10000000.00000000 | /17 | 32766 | 0.0.127.255 |
255.255.0.0 | 11111111.11111111.00000000.00000000 | /16 | 65534 | 0.0.255.255 |
255.254.0.0 | 11111111.11111110.00000000.00000000 | /15 | 131070 | 0.1.255.255 |
255.252.0.0 | 11111111.11111100.00000000.00000000 | /14 | 262142 | 0.3.255.255 |
255.248.0.0 | 11111111.11111000.00000000.00000000 | /13 | 524286 | 0.7.255.255 |
255.240.0.0 | 11111111.11110000.00000000.00000000 | /12 | 1M | 0.15.255.255 |
255.224.0.0 | 11111111.11100000.00000000.00000000 | /11 | 2M | 0.31.255.255 |
255.192.0.0 | 11111111.11000000.00000000.00000000 | /10 | 4M | 0.63.255.255 |
255.128.0.0 | 11111111.10000000.00000000.00000000 | /9 | 8M | 0.127.255.255 |
255.0.0.0 | 11111111.00000000.00000000.00000000 | /8 | 16M | 0.255.255.255 |
254.0.0.0 | 11111110.00000000.00000000.00000000 | /7 | 32M | 1.255.255.255 |
252.0.0.0 | 11111100.00000000.00000000.00000000 | /6 | 64M | 3.255.255.255 |
248.0.0.0 | 11111000.00000000.00000000.00000000 | /5 | 128M | 7.255.255.255 |
240.0.0.0 | 11110000.00000000.00000000.00000000 | /4 | 256M | 15.255.255.255 |
224.0.0.0 | 11100000.00000000.00000000.00000000 | /3 | 512M | 31.255.255.255 |
192.0.0.0 | 11000000.00000000.00000000.00000000 | /2 | 1024M | 63.255.255.255 |
128.0.0.0 | 10000000.00000000.00000000.00000000 | /1 | 2048M | 127.255.255.255 |
0.0.0.0 | 00000000.00000000.00000000.00000000 | /0 | 4096M | 255.255.255.255 |