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IPv4 CIDR Calculator

CIDR (Classless Inter-Domain Routing) notation combines an IP address with a prefix length to represent network ranges. It replaced the older classful addressing system and allows for more efficient IP address allocation. This free online tool calculates IP ranges, subnet masks, broadcast addresses, and usable host counts from CIDR notation. It also shows binary representations and IP class information. All processing happens locally in your browser.

Features

Network

IP Calculations

Calculate network address, broadcast, and usable host ranges.

Calculator

Binary View

See binary representation of network and broadcast addresses.

Info

Quick Reference

Common CIDR reference table included.

Frequently Asked Questions