BMI Calculator
BMI (Body Mass Index) is your weight in kilograms divided by the square of your height in meters, and it is the most widely used indicator for assessing obesity. Just enter your height and weight to instantly see your BMI, weight category, and healthy weight range.
Examples
Height 170 cm, weight 65 kg
BMI = 65 ÷ (1.7 × 1.7) = 65 ÷ 2.89 ≈ 22.5, which falls within the normal range (18.5–22.9).
Height 160 cm, weight 70 kg
BMI = 70 ÷ (1.6 × 1.6) = 70 ÷ 2.56 ≈ 27.3, which falls within Class 1 obesity (25–29.9).
Healthy weight range for 175 cm
Based on the normal BMI range (18.5–22.9), the healthy weight range for someone 175 cm tall is roughly 56.7 kg to 70.1 kg.
FAQ
Is BMI an accurate measure of obesity?
BMI is a simple and widely used indicator, but it cannot distinguish muscle from body fat. Athletes with high muscle mass may show a high BMI even with low body fat. For a more accurate assessment, it is best to also check body fat percentage and waist circumference.
Why do the Asia-Pacific BMI criteria differ from the WHO criteria?
Research shows that at the same BMI, Asians tend to have a higher body fat percentage and a greater risk of diabetes and cardiovascular disease than Western populations. For this reason, the Korean Society for the Study of Obesity classifies a BMI of 25 or higher as obese, a lower threshold than the WHO standard of 30.
How is ideal body weight calculated?
Ideal body weight is commonly calculated as height (m) × height (m) × 21 for women or 22 for men, because a BMI of 21–22 is associated with the lowest mortality rate.
Do the same criteria apply to children and teenagers?
No. For growing children and adolescents, age- and sex-specific BMI percentiles are used instead. A BMI at or above the 85th percentile for the same age and sex is classified as overweight, and at or above the 95th percentile as obese.
Is a low BMI a sign of good health?
Being underweight (BMI below 18.5) also carries health risks, including nutritional deficiencies, osteoporosis, and weakened immunity. Staying within the normal range (18.5–22.9) is the healthiest option.
Abdominal obesity and waist circumference
Even with a normal BMI, abdominal obesity raises the risk of metabolic syndrome. Under the criteria used in Korea, a waist circumference of 90 cm (about 35.4 inches) or more for men, or 85 cm (about 33.5 inches) or more for women, is classified as abdominal obesity.
Abdominal obesity is closely linked to visceral fat and increases the risk of diabetes, high blood pressure, and dyslipidemia. It is best to manage both BMI and waist circumference together.
Healthy weight management
Rapid weight loss can lead to rebound weight gain and muscle loss. A gradual loss of about 0.5–1 kg per week is recommended.
Regular aerobic exercise (at least 150 minutes per week), strength training (at least twice a week), and a balanced diet are the foundations of healthy weight management.
Related Calculators
Korean Age Calculator
Calculate your international age and Korean year age from your date of birth. This free age calculator follows Korea's 2023 age standardization law and also shows your zodiac sign and days until your next birthday.
Percentage Calculator
Find what percent one value is of another, calculate percentage increase or decrease, and get X% of any number. A free percentage calculator for discounts, raises, and ratios.