Get in touch.
Found a bug, spotted a wrong result, or have an idea that would make subnetting easier? We read every message. Pick whichever is easiest below.
General enquiries
Questions about the tool, partnerships, or anything else.
whitewolf@onlinesubnetcalculator.comReport a bug
See a result that looks off? Tell us the exact input and we'll dig in.
whitewolf@onlinesubnetcalculator.comFeature requests
Want a feature the calculator doesn't have yet? We'd love to hear it.
whitewolf@onlinesubnetcalculator.comBefore you write in
Many questions are already answered on the calculator's home page and its FAQ: how to
read a subnet mask, how many hosts a given prefix holds, and how IPv6 subnetting works.
If you're reporting an unexpected result, please include the exact network you entered
(for example 192.168.1.0/26) so we can reproduce it quickly.
A quick note on privacy: the calculator runs entirely in your browser, so we never see what you compute. That also means we can only help with a specific input if you include it in your message. See our Privacy Policy for the details.