Subnetting an IP address (172.16.0.0/12) into 2 subnets

Question

Say I have the private network address 172.16.0.0/12 and I want to split it into 2 subnets.

There are 12 bits used for the network number leaving 20 bit for the host number. I use 1 of these host bits as a subnet number giving me 2 subnets and leaving me with 19 bits for the host number.

This will mean I will have 2^19 - 2 = 524286 IP addresses per subnet?

And the second subnet address will be 172.24.0.0. The broadcast address of the second subnet will be 172.31.255.255

Have I got that correct?

Answer 1

Yes, these numbers are correct. There are several IP subnet calculators on the internet that will help confirm these types of calculation, as well as phone apps.

Note that it is only in niche scenarios that such a large network would be useful, let alone a good idea.