What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation represents the number of bits used for the network portion of an IP address. /24 means 24 bits for network, 8 bits for hosts.

What's the difference between subnet mask and wildcard mask?

Wildcard mask is the inverse of subnet mask. It's used in access control lists (ACLs) and OSPF configurations. For /24: subnet mask is 255.255.255.0, wildcard is 0.0.0.255.

Why are 2 addresses subtracted from usable hosts?

The network address (first) and broadcast address (last) cannot be assigned to hosts, so they're subtracted from the total.

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IPL 2026

IP Subnet Calculator

Calculate network address, broadcast address, subnet mask, and usable host range from any IP address and CIDR notation.

Complete User Guide

Our IP Subnet Calculator helps network administrators and IT professionals quickly calculate subnet details:

Step 1: Enter an IP address (e.g., 192.168.1.1).

Step 2: Select or enter the CIDR notation (e.g., /24).

Step 3: Click 'Calculate' to see network address, broadcast address, subnet mask, wildcard mask, and usable host range.

The calculator also shows IP class and binary subnet mask for educational purposes.

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