Privacy policy
Short version: every calculation runs in your browser, and nothing you type into a tool is sent to us. Last updated 8 July 2026.
What we collect
Nothing you enter into a calculator. Every calculation on SubnetKit, from the subnet calculator to the IPv6 tool, runs as JavaScript in your own browser. The IP addresses, masks, and MAC addresses you type are never transmitted to a server, because there is no server-side processing to send them to.
Cookies
SubnetKit stores a small preference for your light or dark theme choice in your browser's local storage. It never leaves your device and you can clear it any time. If display ads or analytics are enabled on the site (see below), the providers behind them may set their own cookies in your browser.
Third-party ads
SubnetKit may show ads served by third-party networks, such as Google AdSense or Ezoic, to help cover hosting and keep the calculators free. These networks can set cookies or use similar technology in your browser to serve ads and measure how they perform, and some of that technology can be used to personalize which ads you see. Visitors in the EEA and UK are shown a consent prompt, and personalized ad cookies are only set after you consent, in line with Google's EU user consent policy. Declining does not restrict access to any calculator or reference page on the site.
Analytics
SubnetKit may use privacy-conscious, aggregate analytics, or the reporting built into an ad network, to see which pages get traffic and roughly where visitors are from. Analytics never see what you type into a calculator, because that input never leaves your device.
The API and embed widget
The JSON API returns only static reference data and receives none of your input. The embeddable widgetalso calculates in the visitor's browser, so embedding it does not send your visitors' data to us.
Hosting
The site is served as static files from a content delivery network. Standard server logs at the hosting provider may record basic request metadata such as IP address and user agent, as is normal for any website, and these are used only to keep the service running and secure.
Questions
If you have a question about this policy or want to raise a privacy concern, use the contact form. There is no email address to remember, just that one page.
Changes
If this policy changes, the date above will change with it, and material updates will be noted in the changelog.