You can verify your answers with our Binary Decimal Hexadecimal Calculator.

Binary is the base 2 number system which computers use for their calculations, including routing. Computers ‘think’ in binary. Memorizing or being able to quickly calculate the powers of 2 is immensely helpful in being able to subnet quickly. This will save precious time on exams such as the CCNA and also prove valuable in the real world.

The formula for how many valid hosts there are in any particular subnet is 2^{h}-2.

You can also practice your binary conversion and multiples of 16.

Download our **Subnet Cheat Sheet** for all the essential information you need to quickly perform subnet calculations in your head.

If you want to learn more about networking and get the Cisco CCNA certification, we highly recommend the Cisco CCNA Gold Bootcamp as your **CCNA training course**. The CCNA is by far the most in-demand networking certification by employers, and the Gold Bootcamp is the highest rated Cisco course online. It has an average rating of 4.8 from over 30,000 public reviews: