Free online IP subnet calculator. Supports CIDR calculation, subnet division, network and broadcast address computation.
TL;DR: Free IP subnet calculator. Divide by subnet count or host count with automatic mask and address range calculation, runs locally in your browser.
This tool runs entirely in your browser. Open DevTools → Network panel and search your input — it appears in no request.
FAQ
Completely free, no registration required. Perform subnet division calculations directly in your browser — all operations run locally with no usage limits.
subnet-calculator focuses on subnet division — splitting a network into multiple equal subnets and calculating each subnet network address and available range. cidr-calculator focuses on calculating subnet info for a single CIDR (network address, broadcast, mask, etc.).
No. All subnet division calculations run locally in your browser. IP addresses are never sent to any server.
Yes. You can divide by "need N subnets" or "need N hosts per subnet" modes, automatically calculating the required subnet mask and address range for each subnet for easy network planning.