Network address, broadcast, mask and number of hosts for IPv4 and IPv6, with a step-by-step calculation. Splitting a network into subnets and merging a list of addresses into CIDR blocks. For IPv6, splitting a prefix into /64 networks and how it works. Everything is calculated in your browser. The addresses you type are not sent anywhere. How we calculate
The page sets no cookies, uses no analytics and loads no outside scripts or fonts: nothing you type leaves your browser. Like any web server, our host (Cloudflare) keeps standard access logs: IP address, time and browser type, but not what you type into the calculator. The other tools on this site are in Polish only.