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About This Tool
Whether you are designing a network, studying for a certification, or troubleshooting IP addressing issues, this subnet calculator gives you every detail you need in one place. Simply enter an IP address with its CIDR prefix (e.g. 192.168.1.0/24) and get instant results.
The tool calculates subnet mask and wildcard mask in both dotted-decimal and binary, network address, broadcast address, first and last usable host, total and usable host counts, and IP address class. All arithmetic is performed using bitwise operations directly in the browser — no data leaves your device.
For larger blocks (/24 and smaller), the tool also lists the first 64 sub-networks within the block, making it easy to plan address allocation across multiple segments.