Network calculations, made clear.
Calculate, plan and learn together
SubnetTidy combines IPv4 and IPv6 subnet calculators, VLSM planning, exact CIDR aggregation, range conversion, containment checks, subnet splitting and practice. It is designed for students learning subnetting and practitioners planning address space.
Calculations run in your browser. There is no account, working-data database or IP-upload API. Advertising and optional analytics use separate requests.
A clear scope
The tools support address arithmetic and learning. They do not test or change connectivity, routing, security or device configuration. Check the requirements of your devices and providers before using a plan in production.
Primary controls are available in 33 languages and locales. Expanded explanations, some secondary labels, errors and policies are in English and Korean. Other interfaces disclose English fallback. Independent native-speaker review has not yet been performed.