BMI Calculator Using cm and kg
Calculate body mass index for an adult age 20 or older using kilograms and centimeters. The result includes the CDC adult category and the exact formula used.
Written and checked by TheToolNet Editorial Team · Last reviewed: September 27, 2026 · Editorial method
This result is a general educational estimate, may be inaccurate for you, and is not medical advice or a diagnosis. Consult a qualified doctor or other appropriate licensed clinician before using it for treatment, diet, exercise, medication, pregnancy care, or a personal health target.
Calculate adult BMI in metric units
BMI formula using kilograms and centimeters
Convert centimeters to meters, square the height, then divide kilograms by that value: BMI = kg ÷ (cm ÷ 100)². For 70 kg and 175 cm, BMI is approximately 22.9.
CDC adult categories
The CDC adult calculator uses below 18.5, 18.5–24.9, 25.0–29.9, and 30.0 or higher as the main adult category boundaries, with obesity divided into three classes. BMI is a screening measure rather than a diagnosis.
Athletes and muscular adults
BMI cannot distinguish fat mass from muscle, bone, or water. A muscular athlete may therefore have a high BMI without the same body-fat level as another person at the same height and weight. Consider a direct body-composition assessment or the approximate body-fat percentage calculator alongside clinical context.
Older adults
Aging can change muscle and fat distribution even when BMI stays similar. BMI alone does not capture frailty, muscle loss, medical history, or functional status, so older adults should interpret it with a qualified clinician rather than relying on a category label.
Children and teenagers need percentiles
This page intentionally does not label BMI for anyone under 20. The CDC child and teen calculator uses sex-specific BMI-for-age percentiles for ages 2–19.
Frequently asked questions
Is BMI a body-fat percentage?
No. BMI relates weight to height; it does not directly measure fat or separate fat from lean mass.
Can BMI diagnose a health condition?
No. It is one screening measure to consider with history, behaviors, examination findings, and laboratory results.