BMI varies between men and women in terms of healthy body fat distribution, though the formula itself is the same. This guide covers ideal BMI ranges and what the numbers mean for each sex.
BMI Formula (Same for All)
Metric:
BMI = Weight (kg) / Height (m)ยฒ
Imperial:
BMI = (Weight (lbs) ร 703) / Height (in)ยฒ
Standard BMI Categories (WHO)
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 โ 24.9 | Normal weight |
| 25.0 โ 29.9 | Overweight |
| 30.0 โ 34.9 | Obese Class I |
| 35.0 โ 39.9 | Obese Class II |
| 40.0 and above | Obese Class III |
BMI Differences by Sex
Women naturally carry 8โ10% more body fat than men at the same BMI due to hormonal differences and reproductive physiology. A BMI of 22 in a woman represents a higher fat percentage than the same BMI in a man.
Some researchers suggest slightly different thresholds:
- Men: healthy BMI 18.5โ24.9 (same as WHO)
- Women: healthy BMI 18.5โ23.9 (slightly lower upper limit)
However, the standard WHO thresholds are used clinically for both sexes.
BMI by Height โ Quick Reference
Men (medium frame)
| Height | Healthy Weight Range |
|---|---|
| 5'7" (170 cm) | 121โ153 lbs (55โ69 kg) |
| 5'9" (175 cm) | 128โ162 lbs (58โ74 kg) |
| 5'11" (180 cm) | 136โ172 lbs (62โ78 kg) |
| 6'1" (185 cm) | 144โ182 lbs (65โ83 kg) |
Women (medium frame)
| Height | Healthy Weight Range |
|---|---|
| 5'3" (160 cm) | 107โ141 lbs (49โ64 kg) |
| 5'5" (165 cm) | 114โ149 lbs (52โ68 kg) |
| 5'7" (170 cm) | 121โ153 lbs (55โ69 kg) |
| 5'9" (175 cm) | 128โ162 lbs (58โ74 kg) |
Limitations of BMI
BMI is a screening tool, not a diagnosis. It doesn't account for:
- Muscle mass: Athletes often have high BMI despite low body fat
- Age: Older adults may be healthy at lower BMI
- Ethnicity: Asian populations show higher health risks at lower BMI (threshold often 23.0)
- Body fat distribution: Abdominal fat is riskier than fat elsewhere
Waist circumference (above 35 in women, 40 in men) is often a better predictor of metabolic risk.
Use our BMI Calculator to calculate your BMI with both metric and imperial units and see your weight category instantly.