Privacy policy
What BJJMath collects and why. Calculators run in your browser; we don't sell your data.
Last updated: June 2026.
This policy explains what BJJMath collects and why. The short version: the calculators run in your browser, we don't sell your data, and the only information you actively give us is your email if you choose to subscribe.
What the calculators store
The calculators are processed in your browser. The numbers you enter — weight, height, birth year, training frequency — are used to compute a result on your device and are not transmitted to or stored on our servers.
Newsletter and forms
If you submit your email through a signup form, it is processed by our form handler (Netlify) and our email provider (Beehiiv) so we can send you what you asked for. You can unsubscribe at any time using the link in any email. We don't sell or rent your email address.
Analytics
We use Google Analytics 4 to understand which calculators are useful, in aggregate. This uses cookies and collects standard, largely anonymized usage data (pages viewed, approximate region, device type). You can opt out with a browser extension or by blocking cookies.
Affiliate links
When you click an affiliate link, the destination retailer may set its own cookie to attribute a purchase. That activity is governed by their privacy policy, not ours.
Your choices
You can block cookies in your browser, unsubscribe from emails, and request deletion of any email we hold by writing to hello@bjjmath.com.
Children
BJJMath is not directed to children under 13 and we do not knowingly collect their personal information.