BMI Calculator in Kg
Free metric BMI calculator — enter your height in centimetres and weight in kilograms. WHO/NHS-standard formula, instant result, no sign-up.
Select your gender
The BMI formula in kg and cm
BMI = weight (kg) ÷ height (m)²
If your height is in centimetres, divide by 100 first: 175 cm → 1.75 m. Then square it: 1.75 × 1.75 = 3.0625. Finally divide your kg weight: 75 ÷ 3.0625 = BMI 24.5.
The 18.5–24.9 healthy range is the same whatever units you use. The calculator above does all the conversions automatically.
Healthy weight range in kg by height
| Height (cm) | Healthy (BMI 18.5–24.9) |
|---|---|
| 150 cm | 41.6 – 56 kg |
| 155 cm | 44.4 – 59.8 kg |
| 160 cm | 47.4 – 63.7 kg |
| 165 cm | 50.4 – 67.8 kg |
| 170 cm | 53.5 – 72 kg |
| 175 cm | 56.7 – 76.3 kg |
| 180 cm | 60 – 80.7 kg |
| 185 cm | 63.3 – 85.2 kg |
| 190 cm | 66.8 – 89.8 kg |
Prefer stones and pounds? We have a UK-locked version too.
BMI calculator (kg) — common questions
Quick answers to the most common questions
Divide your weight in kilograms by your height in metres squared. So a 70 kg adult who is 1.70 m tall has a BMI of 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 = 24.2. Our calculator does this automatically the moment you enter your numbers.
The standard formula uses metres, but it works just as easily from centimetres: BMI = weight (kg) ÷ ((height in cm ÷ 100)²). For a 175 cm adult weighing 75 kg: 75 ÷ (1.75 × 1.75) = 24.5. The calculator accepts cm directly so you don't have to convert.
No — they give the same result. The metric formula (kg ÷ m²) and the imperial formula ((lbs ÷ in²) × 703) are mathematically equivalent because 703 is just the conversion factor between the two systems. Whether you enter 70 kg / 170 cm or 154 lbs / 5 ft 7 in, you get BMI 24.2.
BMI is a unitless ratio, so the healthy band is the same regardless of input units: WHO and NHS guidance puts the healthy range at BMI 18.5–24.9. For a 1.70 m adult that translates to roughly 53.5–72.0 kg. For 1.80 m it's 60–80.6 kg. Use the calculator to see your personal range.
Toggle the height unit to feet/inches while keeping weight in kilograms. Or convert manually: 1 foot = 0.3048 m, so 5 ft 8 in = 1.7272 m. Then apply BMI = kg ÷ m² as normal. Our calculator handles mixed unit pairs automatically.
The formula is identical for men and women, and accurate as a population-level screen for both. Women carry more essential body fat than men at the same BMI, so for women a body fat percentage and waist-circumference measurement add useful context. The kg-based formula doesn't change the underlying interpretation.
The formula is the same, but the WHO Asia-Pacific guidance and NICE PH53 recommend lower cut-offs for South Asian, Chinese, Black African and Middle Eastern adults: overweight starts at BMI 23 (instead of 25) and obese at BMI 27.5. Our NHS BMI calculator applies these ethnicity-adjusted thresholds automatically.
No — the adult kg/cm formula doesn't apply to children. For ages 2–19, BMI is plotted on age-and-sex percentile charts (CDC growth charts). Use our child & teen BMI calculator instead, which auto-applies the right percentile bands.
Have another question? Browse our full article library or try a free calculator.
Related calculators
BMI Calculator
Most popularThe main BMI tool — metric or imperial, men or women.
Open calculatorBMI Calculator (Stones & Pounds)
UK-locked version: stones, pounds, feet and inches.
Open calculatorHow to Calculate BMI
The formula explained step-by-step in metric, imperial, and Excel.
Open calculatorNHS BMI Calculator
NICE PH53 ethnicity-adjusted thresholds.
Open calculator