IP Subnet Calculator
Calculate network address, broadcast, and host ranges for IPv4 CIDR blocks. 100% client-side deterministic calculation.
Host bits are automatically normalized (e.g., 192.168.1.25/24 becomes 192.168.1.0/24).
Privacy-first
Your data is processed entirely in your browser. We do not upload, store, or transmit your data to any server.
Understanding this Utility
An IP Subnet Calculator performs deterministic mathematical calculations to analyze IPv4 CIDR blocks. It determines network boundaries, host ranges, and binary representations entirely within your browser.
How It Works
The tool parses the IPv4 address and prefix length, then applies bitwise arithmetic to calculate the network address, broadcast address, and subnet mask. All calculations use strict unsigned 32-bit integer math to ensure accuracy.
Host Bits Normalization
If you enter an IP address with host bits set (e.g., `192.168.1.25/24`), the calculator automatically normalizes it to the correct network address (`192.168.1.0/24`). This helps verify the actual network boundary of any given IP.
Special Prefix Cases
This tool uses the classic subnetting model. A `/32` prefix represents a single host (1 usable address). A `/31` prefix is treated as having 0 usable hosts (reserved for network and broadcast in the classic model, though RFC 3021 allows point-to-point use). A `/0` represents the entire IPv4 space.
What This Tool Does NOT Do
This is a pure mathematical calculator. It does not perform network discovery, ping tests, DNS lookups, IPv6 calculations, or routing table analysis. No data is sent over the network.
Privacy & Processing
🔒 **100% Client-Side.** Your IP addresses are processed entirely in your browser's memory using native JavaScript. No data is transmitted, stored, or logged.