Estimate your body fat percentage using the US Navy method — no equipment needed, just a tape measure.
Calculate Body Fat ↓Measure at the widest point. Use a flexible tape measure and measure in the morning.
Men: 2–5% | Women: 10–13%. This is the minimum fat required for basic physiological functions like hormone production, vitamin storage, and organ protection. Going below this range for extended periods is genuinely dangerous and can disrupt hormonal balance — it's not a goal to aim for, even for aesthetic reasons.
Men: 6–13% | Women: 14–20%. This is the typical range seen in competitive athletes and bodybuilders, especially close to competition. It requires very disciplined nutrition and training to reach and, for most people, is difficult to maintain year-round without significant lifestyle sacrifice.
Men: 14–17% | Women: 21–24%. This range represents a visibly fit, healthy body composition that's realistically maintainable long-term for most active adults with consistent training and reasonable diet discipline — a sensible target for general fitness goals rather than competition-level leanness.
Men: 25%+ | Women: 32%+. This range is associated with elevated risk of type 2 diabetes, cardiovascular disease, and metabolic syndrome, particularly when excess fat is stored around the abdomen (visceral fat). A moderate, sustained calorie deficit combined with resistance training to preserve muscle is the recommended approach.
This calculator uses the circumference-based formula developed by the U.S. Navy in the 1980s as a fast field method for estimating body fat without specialised equipment like calipers or DEXA scanning. It uses neck, waist, and (for women) hip measurements, plus height, in a logarithmic equation. Studies comparing it against more precise methods like hydrostatic weighing generally find it accurate within about 3-4 percentage points for most people — reasonably good for a tape-measure method.
The method is less reliable for people with body shapes far from the average build it was calibrated on — very muscular athletes tend to get overestimated body fat because the formula can't tell dense muscle from fat around the waist, while people carrying fat mainly in areas the formula doesn't measure may get underestimated results. For a more precise reading, DEXA scans, hydrostatic weighing, or Bod Pod testing (all requiring specialist equipment) remain the gold standard.
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