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 |
| 70 kg, 175 cm | 154 lbs, 5'9" | 11 st 0 lbs, 5'9" | 22.9 | Normal |
| 85 kg, 180 cm | 187 lbs, 5'11" | 13 st 5 lbs, 5'11" | 26.2 | Overweight |
| 100 kg, 175 cm | 220 lbs, 5'9" | 15 st 10 lbs, 5'9" | 32.7 | Obese |
Common mistakes
- Entering height in metres instead of centimetres (e.g. 1.75 instead of 175)
- Using grams instead of kilograms (e.g. 70000 instead of 70)
- Forgetting decimal places: 1.75 m vs 175 cm — both valid but different fields
Frequently asked questions
How do I convert from cm to inches?
1 cm = 0.394 inches. Or: 1 inch = 2.54 cm. Example: 175 cm = 68.9 inches = 5'8.9".
What if I know my height in metres, not cm?
Multiply by 100. Example: 1.75 m = 175 cm. Our calculator accepts cm only — convert if needed.
Why do most countries use metric for BMI?
The BMI formula (kg/m²) was designed for metric. Imperial conversions add a multiplication factor (703) and rounding errors. Metric is the standard in international medical research.
Is BMI more accurate in metric units?
No, the underlying calculation is identical. Metric just avoids the 703 conversion factor needed for imperial (lbs/in²). Mathematically the result is the same.
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