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.

  • 10.0.0.0 – 10.255.255.255 (10/8 prefix)
  • 172.16.0.0 – 172.31.255.255 (172.16/12 prefix)
  • 192.168.0.0 – 192.168.255.255 (192.168/16 prefix)
  • 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