IPv4 subnet calculator

To use this calculator, simply enter an IPv4 address with optional CIDR notation (e.g., 192.168.1.1/24). If you don't include the CIDR notation, the calculator will assume a default based on the IP class:

• Class A: /8
• Class B: /16
• Class C: /24

The calculator will automatically display all subnet information. You can navigate to adjacent network blocks using the "Previous block" and "Next block" buttons.

CIDR (Classless Inter-Domain Routing) notation consists of an IP address followed by a slash and a number (1-32) that represents the number of consecutive 1's in the subnet mask.

For example:

• /24 represents a subnet mask of 255.255.255.0 (24 consecutive 1's)
• /16 represents a subnet mask of 255.255.0.0 (16 consecutive 1's)
• /8 represents a subnet mask of 255.0.0.0 (8 consecutive 1's)

The CIDR notation determines how many IP addresses are available in a subnet. The formula is 2^(32-prefix), where 'prefix' is the number after the slash.