Frequently Asked Questions
Last updated: June 6, 2026
Yes. All calculations run in your browser using JavaScript. We don't have a database. We don't use cookies for tracking. We don't even have a server that processes your inputs. If you clear your browser data, your history disappears. That's the point.
They're as accurate as the formulas they use — which are the same formulas doctors and researchers use. BMI is a screening tool, not a diagnosis. Body fat estimators (like the Navy method) have a margin of error of about ±3%. We show you the uncertainty, not just the number.
I built these tools for myself first. Then I figured other people might find them useful. The site is supported by advertising (clearly labeled) and affiliate links to products I actually use. No paywalls, no "premium features," no data selling.
Yes — locally. Some tools save your history in your browser's localStorage. This means your data stays on your device and is available when you return. You can clear it anytime by clearing your browser data. We cannot access it.
No. I am not a doctor, dietitian, or personal trainer. I provide tools and write about my own experiences. For personalized medical or nutritional advice, please consult a qualified healthcare professional.
Email contact@bmitool.org with details: what tool you were using, what you entered, what you expected to happen, and what actually happened. Include your browser and device if possible. "It broke" is not helpful — "BMI calculator shows NaN when I enter height 0" is.
Yes. All tools are responsive and work on mobile devices, tablets, and desktops. The charts and calculators adapt to your screen size.
No, and I don't plan to make one. The website works as a progressive web app — you can add it to your home screen on iOS or Android and it will work like a native app. No app store required, no updates to download, no permissions to grant.
I'm a 38-year-old former fintech data analyst living in East Austin, Texas. I have a BS in Statistics from UT Austin and a dog named Pixel who is unimpressed by my spreadsheets. I built BMITool.org because I was frustrated with health calculators that demanded my email or sold my data. Read more about me here.
Yes. Most tools have an export or screenshot feature. You can save charts as images, export data as CSV, or simply screenshot your results. Share them with your doctor, your trainer, or your group chat — whatever helps you.