Subnetting: Powers of 2 You Must Memorize #networking

追加: 2026-05-18

[00:00:02]Every subnetting question comes down to the powers of two. So if you want to learn to subnet fast, memorize these powers of two. Host counts, subnet sizes, magic numbers, all of it.

[00:00:14]Memorize the first 10. And you won't be needing that calculator.

[00:00:20]2 to the 1st is 2. 2 to the 2 is 4. 2 to the 3r is 8. 2 to the 4th is 16. 2 to the 5th is 32. 2 to the 6th is 64. 2 to the 7th is 128. 2 to the 8th is 256. 2 to the 9th is 512. 2 to the 10th is 1024.

[00:00:40]Now a /27 has five host bits. 2 to the 5th is 32. That subnet holds 32 addresses.

[00:00:47]A /28 has four host bits. 2 to the 4th is 16. That subnet holds 16 addresses.

[00:00:56]Do you see the pattern there? Host bits in, power of two