Subnet calculator (IPv4)
Enter an IPv4 address and CIDR prefix; get the network address, broadcast, subnet mask, first and last usable host, and total usable host count. Runs in-browser, no data sent anywhere.
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About this tool
We built this for our own engineers. Vitalytics designs and runs networks for managed clients in regulated sectors — trade-floor LANs, geotechnical site-to-office WANs, healthcare PHI segmentation. If you'd rather not subnet by hand for the next ten years, see our Managed IT service or Azure landing-zone work.
More calculators on the Tools for Engineers hub.