What’s a /19? How many IPs do I get to use with a /20? Well, see the table below!
Usable IPs is the Total IPs. Read more about IPv4 subnetting reference
CIDR | Subnet Mask | Total IPs | Usable IPs |
/32 | 255.255.255.255 | 1 | 1 |
/31 | 255.255.255.254 | 2 | 0 |
/30 | 255.255.255.252 | 4 | 2 |
/29 | 255.255.255.248 | 8 | 6 |
/28 | 255.255.255.240 | 16 | 14 |
/27 | 255.255.255.224 | 32 | 30 |
/26 | 255.255.255.192 | 64 | 62 |
/25 | 255.255.255.128 | 128 | 126 |
/24 | 255.255.255.0 | 256 | 254 |
/23 | 255.255.254.0 | 512 | 510 |
/22 | 255.255.252.0 | 1024 | 1022 |
/21 | 255.255.248.0 | 2048 | 2046 |
/20 | 255.255.240.0 | 4096 | 4094 |
/19 | 255.255.224.0 | 8192 | 8190 |
/18 | 255.255.192.0 | 16,384 | 16,382 |
/17 | 255.255.128.0 | 32,768 | 32,766 |
/16 | 255.255.0.0 | 65,536 | 65,534 |
/15 | 255.254.0.0 | 131,072 | 131,070 |
/14 | 255.252.0.0 | 262,144 | 262,142 |
/13 | 255.248.0.0 | 524,288 | 524,286 |
/12 | 255.240.0.0 | 1,048,576 | 1,048,574 |
/11 | 255.224.0.0 | 2,097,152 | 2,097,150 |
/10 | 255.192.0.0 | 4,194,304 | 4,194,302 |
/9 | 255.128.0.0 | 8,388,608 | 8,388,606 |
/8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
/7 | 254.0.0.0 | 33,554,432 | 33,554,430 |
/6 | 252.0.0.0 | 67,108,864 | 67,108,862 |
/5 | 248.0.0.0 | 134,217,728 | 134,217,726 |
/4 | 240.0.0.0 | 268,435,456 | 268,435,454 |
/3 | 224.0.0.0 | 536,870,912 | 536,870,910 |
/2 | 192.0.0.0 | 1,073,741,824 | 1,073,741,822 |
/1 | 128.0.0.0 | 2,147,483,648 | 2,147,483,646 |
/0 | 0.0.0.0 | 4,294,967,296 | 4,294,967,294 |
What is an IP address?
An IP address or an IP address is an address that identifies a connection to the Internet. The IP address used for information sent on the Internet to reach the right computer.
Every Internet-connected computer has an IP address. Sometimes multiple computers to share the same IP address.
An IP address can be dynamic or static. A dynamic IP address is assigned through a server of the Internet service and address can be changed at each connection point. A static IP address is always the same. One calls it a fixed IP address.
Most ISPs only use dynamic IP addresses to private persons. Such an IP address can thus belong to several different people from different parts of the country from one day to another. There are few operators publish static IP addresses.
There are public and private IP addresses. The private IP addresses are used only in local networks and should never occur in the traffic going over the Internet.
The current standard that manages IP addresses, called IPv4. However, with an increased number of users on the network are IP addresses in IPv4 running out. Within the next few years, most companies, organizations and operators move to the new standard IPv6. IPv6 supports virtually unlimited number of IP addresses.
For private users is expected to transition take place relatively painlessly without the need to upgrade either the hardware or software when using a reasonably modern computer and updated operating system. IPv4 will likely operate in parallel with IPv6 for a long time to come.