IP Address Subnet Calculator
A IP address subnet calculator helps Cisco academy students and network specialists learn how to subnet by making the calculation of subnetting easier. The calculator will display the network address, broadcast address, first host, last host, and CIDR (Classless Inter-Domain Routing) notation of a IP address.
Enter an IP to subnet using the drop down boxes below on the calculator or enter a IP address manually in the box. Set the CIDR prefix size, netmask, wildcard mask, and number of addresses to your preferences. The results will be displayed based on the settings you enter.
The IPAddress.com subnet calculator is free to use. Cisco Academy students sitting for their networking certification will find this calculator very easy to use and helpful when it comes time for the exam.
Network administrators, webmasters, programmers, security professionals, and computer teachers are all professions that use subnetting in their day to day life. These same people work with top technology brands like Cisco, HP, 3Com, Apple, ASUS, Belkin, Netgear, Linksys, and SMC to configure routers, switches, and network security appliances.
A traditional IPv4 subnet has 5 letter classes. A, B, C, D, and E. Only A, B, and C are assigned. D and E are not defined.
- Class A addresses begin with 0 and have their first octet in the range 1 to 126.
- Class B addresses begin with 10 and have their first octet in the range 128 to 191.
- Class C addresses begin with 110 and have their first octet in the range 192 to 223.
| Prefix Size | Network Mask | Total Addresses | Usable Addresses |
|---|---|---|---|
| /1 | 128.0.0.0 | 2,147,483,648 | 2,147,483,646 |
| /2 | 192.0.0.0 | 1,073,741,824 | 1,073,741,822 |
| /3 | 224.0.0.0 | 536,870,912 | 536,870,910 |
| /4 | 240.0.0.0 | 268,435,456 | 268,435,454 |
| /5 | 248.0.0.0 | 134,217,728 | 134,217,726 |
| /6 | 252.0.0.0 | 67,108,864 | 67,108,862 |
| /7 | 254.0.0.0 | 33,554,432 | 33,554,430 |
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
| /9 | 255.128.0.0 | 8,388,608 | 8,388,606 |
| /10 | 255.192.0.0 | 4,194,304 | 4,194,302 |
| /11 | 255.224.0.0 | 2,097,152 | 2,097,150 |
| /12 | 255.240.0.0 | 1,048,576 | 1,048,574 |
| /13 | 255.248.0.0 | 524,288 | 524,286 |
| /14 | 255.252.0.0 | 262,144 | 262,142 |
| /15 | 255.254.0.0 | 131,072 | 131,070 |
| /16 | 255.255.0.0 | 65,536 | 65,534 |
| /17 | 255.255.128.0 | 32,768 | 32,766 |
| /18 | 255.255.192.0 | 16,384 | 16,382 |
| /19 | 255.255.224.0 | 8,192 | 8,190 |
| /20 | 255.255.240.0 | 4,096 | 4,094 |
| /21 | 255.255.248.0 | 2,048 | 2,046 |
| /22 | 255.255.252.0 | 1,024 | 1,022 |
| /23 | 255.255.254.0 | 512 | 510 |
| /24 | 255.255.255.0 | 256 | 254 |
| /25 | 255.255.255.128 | 128 | 126 |
| /26 | 255.255.255.192 | 64 | 62 |
| /27 | 255.255.255.224 | 33 | 30 |
| /28 | 255.255.255.240 | 16 | 14 |
| /29 | 255.255.255.248 | 8 | 6 |
| /30 | 255.255.255.252 | 4 | 2 |
| /31 | 255.255.255.254 | 2 | 2 |
| /32 | 255.255.255.255 | 1 | 1 |
Don’t forget when calculating that a subnet is logical and a subdivision that is visible on a IP address network. If you don’t have a IP to use in the calculator, find out what your IP address is and use it.
