Body Mass Index
Calculator
Understand your body weight in relation to your height, assess your health risk levels, and take informed steps toward a healthier life.
and press Calculate My BMI
How to Use This Calculator
Follow these four simple steps to get your accurate BMI reading.
Choose Your Unit System
Toggle between Metric (centimetres & kilograms) or Imperial (feet/inches & pounds) — whichever you're most comfortable with.
Enter Your Height
Measure your height without shoes, standing straight against a wall. For metric, enter in cm. For imperial, enter feet and remaining inches separately.
Enter Your Weight
Use a reliable scale, weighed at the same time of day (morning, after bathroom) for consistency. Enter in kg or lbs depending on your selected unit.
Review Your Results
Your BMI score and category will appear instantly. Read the contextual information below to understand what your result means for your health.
How BMI is Calculated
The Body Mass Index formula is simple, standardised, and used by healthcare professionals worldwide.
BMI Classification Chart
The World Health Organisation (WHO) defines six BMI categories for adults aged 20 and over.
| BMI Range | Category | Health Risk Level | Description |
|---|---|---|---|
| Below 18.5 | Underweight | Increased Risk | May indicate malnutrition, eating disorders, or other health concerns. Immune function may be compromised. |
| 18.5 – 24.9 | Normal Weight | Low Risk | Associated with the lowest risk of weight-related health conditions. This is the optimal range for most adults. |
| 25.0 – 29.9 | Overweight | Elevated Risk | Slightly elevated risk of cardiovascular disease, type 2 diabetes, and high blood pressure. Lifestyle changes recommended. |
| 30.0 – 34.9 | Obese (Class I) | High Risk | Significant increase in risk for chronic conditions. Medical consultation is advised. Weight loss of 5–10% can yield measurable health benefits. |
| 35.0 – 39.9 | Obese (Class II) | Very High Risk | Serious risk of metabolic disease. Often associated with sleep apnea, joint problems, and reduced mobility. |
| 40.0 and above | Obese (Class III) | Extremely High Risk | Morbid obesity significantly shortens life expectancy. Medical intervention including possible surgery may be considered. |
Healthy Weight Reference Chart
The table below shows the approximate healthy weight range (BMI 18.5–24.9) for common heights in both metric and imperial units.
| Height (cm) | Height (ft / in) | Min Healthy Weight | Max Healthy Weight | Midpoint (Ideal) |
|---|---|---|---|---|
| 150 cm | 4'11" | 41.6 kg / 92 lbs | 56.2 kg / 124 lbs | 48.9 kg / 108 lbs |
| 155 cm | 5'1" | 44.4 kg / 98 lbs | 59.9 kg / 132 lbs | 52.1 kg / 115 lbs |
| 160 cm | 5'3" | 47.4 kg / 104 lbs | 63.8 kg / 141 lbs | 55.6 kg / 123 lbs |
| 163 cm | 5'4" | 49.2 kg / 108 lbs | 66.2 kg / 146 lbs | 57.7 kg / 127 lbs |
| 165 cm | 5'5" | 50.4 kg / 111 lbs | 67.9 kg / 150 lbs | 59.1 kg / 130 lbs |
| 168 cm | 5'6" | 52.2 kg / 115 lbs | 70.4 kg / 155 lbs | 61.3 kg / 135 lbs |
| 170 cm | 5'7" | 53.5 kg / 118 lbs | 72.1 kg / 159 lbs | 62.8 kg / 138 lbs |
| 173 cm | 5'8" | 55.4 kg / 122 lbs | 74.6 kg / 164 lbs | 65.0 kg / 143 lbs |
| 175 cm | 5'9" | 56.7 kg / 125 lbs | 76.4 kg / 168 lbs | 66.6 kg / 147 lbs |
| 178 cm | 5'10" | 58.7 kg / 129 lbs | 79.0 kg / 174 lbs | 68.8 kg / 152 lbs |
| 180 cm | 5'11" | 59.9 kg / 132 lbs | 80.7 kg / 178 lbs | 70.3 kg / 155 lbs |
| 183 cm | 6'0" | 62.0 kg / 137 lbs | 83.5 kg / 184 lbs | 72.7 kg / 160 lbs |
| 185 cm | 6'1" | 63.4 kg / 140 lbs | 85.3 kg / 188 lbs | 74.3 kg / 164 lbs |
| 188 cm | 6'2" | 65.4 kg / 144 lbs | 88.1 kg / 194 lbs | 76.7 kg / 169 lbs |
| 190 cm | 6'3" | 66.8 kg / 147 lbs | 89.9 kg / 198 lbs | 78.3 kg / 173 lbs |
| 193 cm | 6'4" | 68.9 kg / 152 lbs | 92.8 kg / 205 lbs | 80.9 kg / 178 lbs |
Why Weight Management Matters
Maintaining a healthy weight is one of the most impactful things you can do for your long-term health and quality of life.
Heart Health
Excess body fat, particularly around the abdomen, raises cholesterol levels, blood pressure, and triglycerides — all major risk factors for cardiovascular disease, heart attacks, and stroke. Even a 5–10% reduction in body weight can measurably improve heart health markers.
Diabetes Prevention
Being overweight is the single greatest modifiable risk factor for type 2 diabetes. Adipose tissue (fat) causes insulin resistance. Studies show that losing just 7% of body weight reduces the risk of developing type 2 diabetes by up to 58% in at-risk individuals.
Joint & Mobility Health
Every extra kilogram of body weight places approximately 4 kg of additional pressure on your knee joints. Maintaining a healthy weight dramatically reduces the risk of osteoarthritis, joint inflammation, and mobility loss as you age.
Mental Wellbeing
Regular physical activity and healthy weight are strongly linked to lower rates of depression and anxiety. Body weight affects hormonal balance, sleep quality, and self-esteem — all deeply connected to mental and emotional wellness.
Sleep Quality
Obesity is the leading risk factor for obstructive sleep apnea, a condition where breathing repeatedly stops during sleep. Poor sleep creates a vicious cycle — increasing hunger hormones (ghrelin) and reducing fullness hormones (leptin), making weight management even harder.
Cancer Risk Reduction
Excess body fat is linked to at least 13 types of cancer, including breast, colon, and kidney cancer. Adipose tissue produces excess estrogen and inflammatory cytokines that can promote tumor growth. The American Cancer Society estimates 8% of all cancers are related to excess weight.
Understanding BMI — Deeper Health Context
BMI is a starting point. Here's what the research says about its strengths, limitations, and what else to consider.
Conditions Linked to High BMI
- Type 2 diabetes and insulin resistance
- Hypertension (high blood pressure)
- Cardiovascular disease and stroke
- Obstructive sleep apnea
- Non-alcoholic fatty liver disease (NAFLD)
- Polycystic ovary syndrome (PCOS)
- Osteoarthritis and joint pain
- Certain cancers (breast, colon, endometrial)
- Gastroesophageal reflux disease (GERD)
- Depression and reduced quality of life
Conditions Linked to Low BMI
- Malnutrition and micronutrient deficiencies
- Anemia (iron deficiency)
- Osteoporosis and stress fractures
- Reduced immune function
- Hormonal disruptions and infertility
- Anorexia nervosa and eating disorders
- Muscle wasting (sarcopenia)
- Impaired wound healing
- Hair loss and skin problems
- Fatigue, brain fog, and poor concentration
BMI Limitations — What It Doesn't Measure
- Does not distinguish between fat and muscle mass
- Does not account for fat distribution (belly vs. hips)
- Underestimates health risk in South Asian populations
- May overestimate risk in highly muscular individuals
- Does not account for age-related muscle loss in older adults
- Does not reflect metabolic health or fitness level
- Waist circumference is a complementary, important metric
- Body fat percentage gives a more complete picture
Complementary Health Metrics to Track
- Waist circumference: Under 88 cm (women) / 102 cm (men)
- Waist-to-hip ratio: Under 0.85 (women) / 0.90 (men)
- Body fat %: 21–33% (healthy women), 8–19% (healthy men)
- Blood pressure: Below 120/80 mmHg
- Fasting blood glucose: Below 5.6 mmol/L (100 mg/dL)
- Resting heart rate: 60–100 bpm (lower = more fit)
- VO2 max: Measure of cardiovascular fitness
- Regular bloodwork: Cholesterol, HbA1c, thyroid panel
Evidence-Based Tips for a Healthy Weight
Small, consistent changes compound into lasting results. These strategies are backed by clinical research.
Eat Whole, Minimally Processed Foods
Focus on vegetables, legumes, fruits, whole grains, and lean proteins. Reduce ultra-processed foods high in added sugar and refined carbohydrates.
150 Minutes of Moderate Activity Per Week
WHO recommends at least 150–300 minutes of moderate aerobic activity weekly. Brisk walking, cycling, swimming — all count.
Include Strength Training
Building muscle increases your resting metabolic rate, helping you burn more calories at rest. Aim for 2 resistance training sessions per week.
Prioritise Sleep (7–9 Hours)
Sleep deprivation increases hunger hormones by 24% and cravings for calorie-dense foods. Quality sleep is fundamental to weight regulation.
Stay Hydrated
Drinking water before meals reduces calorie intake. Aim for 8–10 cups daily. Replace sugary drinks with water or herbal teas.
Manage Stress Levels
Chronic stress raises cortisol, which promotes fat storage around the abdomen. Mindfulness, yoga, and breathing exercises are effective tools.
Track, But Don't Obsess
Light food and activity journalling increases self-awareness. Apps like MyFitnessPal can help, but take a flexible, compassionate approach — not a restrictive one.
Work With Healthcare Professionals
A registered dietitian, GP, or endocrinologist can identify underlying causes (thyroid issues, hormonal imbalances) that affect weight despite healthy habits.