Weight Converter + BMI Calculator
Convert a weight between kilograms, pounds and stone and get your BMI and weight category in one step.
How it works
1 kg = 2.20462 lb = 0.157473 st · BMI = weight(kg) ÷ height(m)² · Normal 18.5–24.9, overweight 25–29.9, obese ≥30
Whatever unit you weigh yourself in, BMI is defined in metric terms — kilograms divided by height in metres squared. This tool converts your weight to kilograms and your height to metres first, so you can enter pounds and inches and still get a correct BMI, along with the same weight expressed in kg, lb and stone.
Worked example
70 kg equals 154.3 lb or 11.02 stone. At 170 cm (1.70 m) the BMI is 70 ÷ 1.70² = 70 ÷ 2.89 = 24.2 — the normal-weight range, just under the 25 overweight line.
Frequently asked questions
How many pounds are in a kilogram?
One kilogram is about 2.2046 pounds. One stone is 14 pounds, or roughly 6.35 kilograms, so 70 kg is about 11 stone.
Does the weight unit change my BMI?
No. The calculator converts everything to kilograms and metres before computing BMI, so 70 kg and 154.3 lb give exactly the same BMI at the same height.
What BMI is considered healthy?
For adults, 18.5 to 24.9 is the normal range, 25 to 29.9 is overweight and 30 or above is obese. BMI does not distinguish muscle from fat, so athletes may read high without excess fat.
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Educational estimate only — not medical advice, diagnosis or treatment. Consult a qualified clinician for health decisions.