BMI Calculator
Calculate your Body Mass Index (BMI) to assess your weight category and get personalized health recommendations based on your measurements.
Your Measurements
BMI Categories
| BMI Range | Category | Status |
|---|---|---|
| < 16.0 | Severe Thinness | |
| 16.0 - 16.9 | Moderate Thinness | |
| 17.0 - 18.4 | Mild Thinness | |
| 18.5 - 24.9 | Normal Weight | |
| 25.0 - 29.9 | Overweight | |
| 30.0 - 34.9 | Obese Class I | |
| 35.0 - 39.9 | Obese Class II | |
| ≥ 40.0 | Obese Class III |
Understanding BMI
What is BMI?
Body Mass Index (BMI) is a measure of body fat based on height and weight. It”s calculated by dividing weight in kilograms by height in meters squared (kg/m²).
Formula: BMI = weight(kg) ÷ height(m)²
BMI Limitations
- • Doesn”t distinguish between muscle and fat
- • May not be accurate for athletes
- • Different standards for different ethnicities
- • Doesn”t consider body fat distribution
- • Less accurate for elderly individuals
Health Tips
- • Maintain a balanced, nutritious diet
- • Exercise regularly (150 min/week)
- • Stay hydrated
- • Get adequate sleep (7-9 hours)
- • Consult healthcare providers regularly
- • Focus on overall health, not just weight
Important Disclaimer
This BMI calculator is for educational purposes only and should not replace professional medical advice. BMI is just one tool to assess health status. Always consult with healthcare professionals for personalized health assessments and recommendations, especially if you have medical conditions or concerns.
BMI by Age — What Changes Over Time
The standard WHO BMI categories (18.5–24.9 for normal) apply to adults aged 18–65. However, body composition changes with age, and the relationship between BMI and health risk shifts accordingly.
| Age Group | Suggested Healthy BMI | Notes |
|---|---|---|
| 18–24 | 18.5–24.9 | Standard WHO range; muscle mass is typically at its peak |
| 25–34 | 18.5–24.9 | Weight gain may begin; focus on maintaining muscle mass |
| 35–54 | 18.5–24.9 | Gradual fat gain and muscle loss; activity level becomes critical |
| 55–64 | 23–27 | Slightly higher BMI may be protective; consult physician |
| 65+ | 23–29 | Higher BMI can protect against fractures and illness; sarcopenia risk |
For children and teenagers, BMI is interpreted differently using age- and sex-specific percentiles rather than fixed cutoffs. A BMI at or above the 85th percentile is considered overweight, and at or above the 95th percentile is obese. Always use a pediatric BMI chart for anyone under 18.
BMI Thresholds for Asian Populations
Research has shown that people of Asian descent tend to carry a higher proportion of body fat and develop metabolic complications (like type 2 diabetes and cardiovascular disease) at lower BMI values than Western populations. The World Health Organization and several Asian health authorities recommend lower cutoff points:
Standard WHO Categories
- Underweight< 18.5
- Normal Weight18.5–24.9
- Overweight25.0–29.9
- Obese≥ 30.0
Recommended Asian Cutoffs
- Underweight< 18.5
- Normal Weight18.5–22.9
- Overweight (at risk)23.0–27.4
- Obese≥ 27.5
These recommendations are used in countries including China, Japan, South Korea, Singapore, and India. If you are of South Asian, East Asian, or Southeast Asian descent, consider these lower thresholds when interpreting your BMI result and consult your healthcare provider for personalized advice.
Beyond BMI — Better Ways to Assess Body Composition
BMI is a useful population-level screening tool, but it has well-known limitations. The following measures provide a more complete picture of your health and body composition:
Waist Circumference
Measures abdominal fat directly. Health risk increases above 94 cm (37 in) for men and 80 cm (31.5 in) for women. Visceral fat around the abdomen is strongly linked to cardiovascular disease, diabetes, and metabolic syndrome.
Waist-to-Hip Ratio (WHR)
Divide waist measurement by hip measurement. A ratio above 0.90 for men or 0.85 for women indicates higher central obesity risk. WHR is considered a better predictor of cardiovascular risk than BMI alone.
Waist-to-Height Ratio (WHtR)
Divide waist circumference by height. A ratio below 0.5 is generally considered healthy for adults. Some research suggests this is an even stronger predictor of cardiometabolic risk than BMI or WHR.
Body Fat Percentage
Directly measures the proportion of fat to total body mass. Healthy ranges: 10–20% for men, 18–28% for women (varies by age and fitness level). Measured by DEXA scan, hydrostatic weighing, air displacement plethysmography, or bioelectrical impedance.
Lean Mass & Muscle Quality
Muscle mass is metabolically active tissue that improves insulin sensitivity and supports healthy aging. Sarcopenia (loss of muscle) affects up to 30% of adults over 60 and can occur even in people with a "normal" BMI. Strength training is the most effective intervention.
Metabolic Blood Markers
Fasting glucose, HbA1c, lipid panel (HDL, LDL, triglycerides), and blood pressure provide a comprehensive view of metabolic health that BMI cannot capture. A person with a normal BMI can still have elevated metabolic risk ("metabolically obese, normal weight").
Evidence-Based Ways to Improve Your BMI and Health
Nutrition
- • Prioritize whole foods: vegetables, legumes, whole grains, lean proteins
- • Reduce ultra-processed foods, added sugars, and refined carbs
- • Practice mindful eating — eat slowly and stop at 80% full
- • A calorie deficit of 500 kcal/day leads to roughly 0.5 kg loss per week
- • High-protein diets (1.2–1.6 g/kg body weight) help preserve muscle during weight loss
Exercise
- • 150–300 min/week of moderate aerobic activity (walking, cycling, swimming)
- • Strength training 2–3 times/week to preserve and build lean mass
- • HIIT (High-Intensity Interval Training) is time-efficient and improves metabolic health
- • Reduce prolonged sitting — take breaks every 30–60 minutes
- • Even 10-minute walks after meals improve insulin sensitivity
Lifestyle
- • Sleep 7–9 hours per night — poor sleep increases hunger hormones (ghrelin)
- • Manage chronic stress — cortisol promotes fat storage especially around the abdomen
- • Stay hydrated — sometimes thirst is mistaken for hunger
- • Track progress beyond the scale: measure waist, take photos, monitor energy levels
- • Work with a registered dietitian for personalised guidance