Conversion examples
Same body, three unit systems. The BMI value is identical regardless of the units you use.
| Metric | Imperial | Stones | BMI | Category |
|---|---|---|---|---|
| 60 kg, 165 cm | 132 lbs, 5'5" | 9 st 6 lbs, 5'5" | 22.0 | Normal |
| 73 kg, 178 cm | 160 lbs, 5'10" | 11 st 6 lbs, 5'10" | 23.0 | Normal |
| 91 kg, 183 cm | 200 lbs, 6'0" | 14 st 4 lbs, 6'0" | 27.1 | Overweight |
| 113 kg, 178 cm | 250 lbs, 5'10" | 17 st 12 lbs, 5'10" | 35.9 | Obese |
Common mistakes
- Mixing systems: weight in lbs but height in cm
- Using total inches vs feet+inches (entering 70 instead of 5'10")
- Forgetting the 703 conversion factor when calculating manually
Frequently asked questions
Why is the imperial BMI formula different?
BMI is fundamentally weight/height² in metric units (kg/m²). To use imperial (lbs/in²) you multiply by 703 to compensate for the unit difference. Our calculator does this automatically.
How do I convert pounds to kilograms?
1 lb = 0.4536 kg. Example: 160 lbs = 72.6 kg. Or divide pounds by 2.205.
How do I convert feet/inches to centimetres?
1 inch = 2.54 cm; 1 foot = 30.48 cm. Example: 5'10" = 70 inches = 178 cm.
Is BMI calculated the same way in the US and Europe?
Yes, the formula and cutoffs are identical (overweight at 25, obese at 30). The only difference is the input units. NIH and CDC use the same WHO classifications.
What's a healthy weight in pounds for me?
Depends on your height. For BMI 22 (mid-normal range): 5'4" = 128 lbs; 5'8" = 144 lbs; 6'0" = 162 lbs; 6'4" = 181 lbs.
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