IP Subnet Calculator


To use the IP Subnet Calculator

Enter your IP address and subnet mask details in the subnet calculator below.  Our subnet calculator returns with both decimal and binary calculations for the Address, Netmask,  Wildcard Mask,  Network, Broadcast, first and last ip address on the subnet, as well as total number of usable ip addresses. [maj update=”02/06/15″]

Don’t miss our articles to understand the theory:


– Enter your ip address and either subnet mask or slash cidr notation.

For example –

  • (reverse/wildcard mask)
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RouterFreak IP Subnet Calculator

Subnet Calculator

From Wikipedia, the free encyclopedia
Creating a subnet by dividing the host identifier

subnetwork, or subnet, is a logically visible subdivision of an IP network.[1] The practice of dividing a single network into two or more networks is calledsubnetting and the networks created are called subnetworks or subnets.

All computers that belong to a subnet are addressed with a common, identical, most-significant bit-group in their IP address. This results in the logical division of an IP address into two fields, a network or routing prefix and the rest field or host identifier. The rest field is an identifier for a specific “host” — either a computer, or a device, or specific network interface on a computer or device.



Senior Network Engineer, technology enthusiast, guitar and bass player. Joe Wilson is the creator of RouterFreak.com as well as other niche websites that can be found around on the Internets.

What do you think about this article?


  1. here is a mobile friendly subnet calculator https://subnet.ninja check it out !

  2. Review by Pierre-an Sajous for Rating: I just took the test today and I’m still in shock about passing the CCNA. About six weeks ago I deiedcd to get serious and start studying for this test. I bought the Cisco Press books and the CCNA for Dummies’ book. It turns out that I didn’t even use the Dummies’ book. The Cisco Press Library comes with two books, which I read both cover to cover. After reading both books I moved to the CDs that also comes with this set, which have a lot of useful material. The Boson practice exams that come with the book, I think are the most useful. The questions that the practice exams asks are very similar to the questions that the real test asks. With the combination of both the book and the practice exams you will be well prepared. Practicing with all the tricky questions really makes you learn the material to the smallest detail. The DVDs that come with the book are pretty lame and dry, I didn’t even use them. I do what to clarify that I did have previous hands on experience with Cisco routers, but I used a free simulator to brush up on some of my skills. This book set is a must and I probably would not have passed without it. I was really nervous walking into the exam, but the resources that this book set provides prepared me very well for the exam.

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