BMI treats muscle and fat the same. That's why Tom Brady is "overweight" and The Rock is "obese" according to BMI. Body Fat Calculator uses the science-backed U.S. Navy circumference method to give you a more accurate picture of your body composition. 🔒 Privacy-first: All calculations happen in your browser (zero data collection) ⚡ Instant: No signup, no payment, no waiting 📚 Educational: Explains what your body fat % means for your health 📱 Works everywhere: Mobile, tablet, desktop
👋 Hey Product Hunt! I'm the maker of Body Fat Calculator.
**Why I built this:**
Six months into my fitness journey, BMI told me I was "overweight" (25.1). But I could see my abs. I was hitting PRs every week.
That's when I realized BMI is broken. It's from 1832 and treats muscle like fat.
DEXA scans are the gold standard (±1-2% accuracy) but cost $150 each. That's $1,800/year if you track monthly.
The U.S. Navy solved this in 1984 with a tape measure. Accuracy: ±3-4%. Cost: $0.
So I built this tool with three principles:
1. **Privacy-first**: All calculations happen in your browser. I literally can't see your data.
2. **Zero barriers**: No signup, no payment, no email.
3. **Educational**: Getting "17% body fat" is meaningless without context.
**Tech stack:**
- Pure JavaScript (zero dependencies)
- No backend (just HTML/CSS/JS)
- Hosted on Netlify
Happy to answer any questions! What would you add/change?
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