IP Addressing & Subnetting

IP Subnetting Calculator — Interactive Subnet Visualizer

Subnetting confuses a lot of students because it lives in binary. This interactive subnet calculator shows the network and host bits in colour as you change the prefix, and computes the network address, broadcast address, usable host range, and host count instantly — so the /24, /26, /30 rules finally make sense.

What you can do in this simulation

• Type any IPv4 address and slide the prefix from /8 to /32 to watch every value update live
• See the 32 bits split into network bits (blue) and host bits (green) as the mask changes
• Read off the network address, broadcast address, and first/last usable host automatically
• Watch the usable-host count halve each time you add a network bit
• Check whether an address is in a private range (10/8, 172.16/12, 192.168/16) and its class

Concepts covered

subnetting · IP addressing · subnet mask · CIDR · network and broadcast address · private IP ranges

Free to use in your browser — no signup required. Found a bug or have an idea to make it better? Tell us.