What is a healthy BMI?

By the WHO standard, a BMI of 18.5–24.9 is normal, below 18.5 is underweight, 25–29.9 overweight and 30 or more obese (class I 30–34.9, II 35–39.9, III 40+). The Chinese standard is stricter: normal is 18.5–23.9, overweight 24–27.9 and obese 28+, because Asians tend to have more body fat at the same BMI.

Is BMI accurate for muscular people?

BMI only uses height and weight and can't tell muscle from fat. Athletes may have a high BMI without excess fat, while older adults may have a normal BMI with high body fat. Combine it with waist circumference or body-fat percentage for a fuller picture.

What's the difference between BMR and TDEE?

BMR is the energy your body burns at complete rest; TDEE is BMR multiplied by an activity factor and includes daily movement and exercise. Eating about 500 kcal below TDEE typically leads to roughly 0.5 kg (1 lb) of weight loss per week; avoid going below your BMR.

Can children or pregnant women use it?

No. The categories apply to adults aged 18 and over. Children and teens are assessed with age- and sex-specific BMI percentiles, and pregnant or breastfeeding women should follow medical advice. Results are for information only and are not medical advice.

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⚖️BMI Calculator - Body Mass Index, Healthy Weight & BMR Calculator

BMI (body mass index) = weight (kg) ÷ height (m)², the most common screening measure for weight status. Enter your height and weight to get your BMI instantly, classified by the WHO standard (18.5–24.9 normal, 25–29.9 overweight, 30+ obese, with obesity classes I–III) or the stricter Chinese standard, shown on a colored gauge. You'll also see the healthy weight range for your height and how much to gain or lose to reach it. Add age and sex to calculate your basal metabolic rate (BMR) with the Mifflin-St Jeor equation, total daily energy expenditure (TDEE) by activity level, and calorie targets for fat loss or lean gain. Metric and imperial units supported.

Free · No sign-up · Runs in your browserLast updated: 2026-10-26

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How to use BMI Calculator

1Choose metric (cm/kg) or imperial (ft·in/lb) and enter height and weight
2Read your BMI, category and healthy weight range; switch between WHO and Chinese standards
3Optionally add sex, age and activity level to see BMR and daily calories

FAQ

What is a healthy BMI?: By the WHO standard, a BMI of 18.5–24.9 is normal, below 18.5 is underweight, 25–29.9 overweight and 30 or more obese (class I 30–34.9, II 35–39.9, III 40+). The Chinese standard is stricter: normal is 18.5–23.9, overweight 24–27.9 and obese 28+, because Asians tend to have more body fat at the same BMI.
Is BMI accurate for muscular people?: BMI only uses height and weight and can't tell muscle from fat. Athletes may have a high BMI without excess fat, while older adults may have a normal BMI with high body fat. Combine it with waist circumference or body-fat percentage for a fuller picture.
What's the difference between BMR and TDEE?: BMR is the energy your body burns at complete rest; TDEE is BMR multiplied by an activity factor and includes daily movement and exercise. Eating about 500 kcal below TDEE typically leads to roughly 0.5 kg (1 lb) of weight loss per week; avoid going below your BMR.
Can children or pregnant women use it?: No. The categories apply to adults aged 18 and over. Children and teens are assessed with age- and sex-specific BMI percentiles, and pregnant or breastfeeding women should follow medical advice. Results are for information only and are not medical advice.