Privacy
Privacy, in plain words
Build the Run is a set of free calculators. There are no accounts, no ads and no tracking cookies. The numbers you type into a calculator are processed in your browser and are not sent to us.
What stays on your device
- Your notes on the home page are saved in your browser's local storage on this device. We never receive them. Clearing your site data removes them.
- Preferences such as light or dark mode and your preferred units (miles or kilometers, ml or fl oz) are stored the same way.
- Which tools are available. Each page asks this site which tools are switched on, and your browser remembers the answer. The request contains nothing about you beyond what any page request does.
- Shared links put your inputs in the web address (for example
?d=10&t=0:50:00) so the person you send it to sees the same numbers. Only share a link if you're comfortable with them seeing those values.
What we collect
Nothing about you personally. We don't run analytics at the moment. If that changes, we'll use a privacy-friendly option and update this page.
Third parties
- Hosting. The site is served by Vercel, which may keep standard server logs (such as IP address and pages requested) for security and operations.
- Fonts. Pages load the Inter typeface from Google Fonts, so your browser contacts Google to fetch it.
- Notes export. Downloading notes as Word or PDF loads open-source libraries from public CDNs (unpkg and cdnjs) the first time you use it. Markdown export needs nothing external.
Health information
The heart-rate, training-pace and fuel tools give general estimates for fitness, not medical advice. Check with a doctor before starting or changing an exercise or nutrition plan, especially if you have a health condition.