content from : https://www.mindwerks.net/online-tools/ip-calc/

Subnet Calculator
Network Class A B C	First Octet Range
IP Address . . .	Hex IP Address
Subnet Mask 255.255.255.0 255.255.255.128 255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252	Wildcard Mask
Subnet Bits 0 1 2 3 4 5 6	Mask Bits 24 25 26 27 28 29 30
Maximum Subnets 1 2 4 8 16 32 64	Hosts per Subnet 254 126 62 30 14 6 2
Host Address Range
Subnet ID	Broadcast Address
Subnet Bitmap

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