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Subnet Calculator

Calculate IP subnet details including network address, broadcast address, usable hosts, wildcard mask, and subnet splitting

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About This Tool

Subnet Calculator is an online tool that computes IP subnet details from any IP address and CIDR prefix. It calculates network address, broadcast address, usable host range, wildcard mask, and binary subnet mask, and can split a network into multiple equal-sized subnets — all processed locally in your browser.

Key Features

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Use Cases

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Frequently Asked Questions

What is the Subnet Calculator?

The Subnet Calculator is an online developer tool that calculates IP subnet details including network address, broadcast address, usable hosts, wildcard mask, and subnet splitting. It runs entirely in your browser with no data sent to any server.

What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation represents an IP address and its subnet mask in a compact format like 192.168.1.0/24. The number after the slash indicates how many bits are used for the network portion, with the remainder for host addresses.

What is the difference between network and broadcast addresses?

The network address is the first address in a subnet (all host bits zero) and identifies the subnet itself. The broadcast address is the last address in a subnet (all host bits one) and is used to send data to all hosts in the subnet simultaneously.

How many usable hosts are in a /24 subnet?

A /24 subnet provides 256 total addresses (2^8), with 254 usable host addresses after reserving the network and broadcast addresses. The calculator automatically displays this for any subnet you enter.

What is a wildcard mask?

A wildcard mask is the inverse of a subnet mask, used primarily in Cisco router ACLs and OSPF configurations. It is calculated by subtracting the subnet mask from 255.255.255.255. For example, a /24 subnet mask (255.255.255.0) has a wildcard of 0.0.0.255.