BMI from kg and cm: three examples
- 55 kg, 160 cm: 55 ÷ 2.56 = 21.5 (healthy).
- 78 kg, 172 cm: 78 ÷ 2.9584 = 26.4 (overweight).
- 102 kg, 183 cm: 102 ÷ 3.3489 = 30.5 (obesity class I).
Unit conversions
- 1 inch = 2.54 cm; 1 foot = 30.48 cm; 5 ft 7 in = 170.2 cm.
- 1 kg = 2.2046 lb; 1 lb = 0.4536 kg.
- 1 stone = 14 lb = 6.35 kg; 10 st 7 lb = 147 lb = 66.7 kg.
The calculator converts automatically, so you can enter whichever units you know and read your healthy weight range back in the same units.
Healthy weight in kilograms by height
The weight in kg at the bottom (BMI 18.5) and top (BMI 24.9) of the healthy range, and where obesity begins (BMI 30):
| Height | BMI 18.5 | BMI 24.9 | BMI 30 |
|---|---|---|---|
| 150 cm | 41.6 kg | 56.0 kg | 67.5 kg |
| 155 cm | 44.4 kg | 59.8 kg | 72.1 kg |
| 160 cm | 47.4 kg | 63.7 kg | 76.8 kg |
| 165 cm | 50.4 kg | 67.8 kg | 81.7 kg |
| 170 cm | 53.5 kg | 72.0 kg | 86.7 kg |
| 175 cm | 56.7 kg | 76.3 kg | 91.9 kg |
| 180 cm | 59.9 kg | 80.7 kg | 97.2 kg |
| 185 cm | 63.3 kg | 85.2 kg | 102.7 kg |
| 190 cm | 66.8 kg | 89.9 kg | 108.3 kg |
| 195 cm | 70.3 kg | 94.7 kg | 114.1 kg |
How to measure for an accurate BMI
- Height: stand barefoot with heels, back and head against a wall; rest a flat object on your head and mark the wall.
- Weight: weigh first thing in the morning, after using the toilet, in light clothing, on a hard floor.
- Consistency: use the same scale at the same time of day when you recheck — daily weight can move by 1–2 kg with food and fluid.